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MG MGB GT V8 Factory Originals Technical - V8 Conversion Diff upgrade ?

I am in the process of doing a V8 conversion on my 79GT using 3.5lt rover motor and possibly Supra 5 speed box. Do I need to change my diff which is original and if so what to. What feedback is there on the Supra box, I have spoken briefly to Geoff Dello Automotive in Sydney, he recommended the box as it is easier to fit?
I also need a list of other engine modifications that I need to do to carry out the conversion, e.g. oil pump, alternator, front suspension?
T Zorzo

Do you have some further information upon the final reduction of the Supra box?
Most gearboxes in these conversions use @ o.8 final drive ratios and this work well with a 3.08 to 3.31 diff.
more details would be great, you see


The stock MGB diff has a ratio of 3.909:1. That's quite a big difference in ratio from the 3.08:1 or 3.31:1 that Ralph correctly stated usually work well with typical conversion fifth-gear rations. But there are other variables including tire size plus personal preference and priorities (e.g. fuel economy vs quickness).

Something that might help you decide is Dan Masters' clever little "Excel" axle-ratio tool:
(note: it doesn't contain any macros.) A little more explanation about it is included in this article:

Gear ratio is only one reason why you might want to change rear axles. Here are a few others:
1. your MGB axle might be worn out.
2. you might like to have a limited slip differential (and an LSD for the MG axle would be expensive)
3. you might want a stronger axle (although the MGB "Salisbury" axle is probably plenty strong for most of us.)
4. you might want to change/upgrade brakes (there are more disc brake options for some other axles, although some people do upgrade MG brakes without changing axles.)
5. you might want wider track or a different wheel lug pattern, or...

Despite these reasons, many people complete the engine conversion and drive the car for awhile before undertaking an axle swap... Divide and conquer!

"other engine modifications that I need to do to carry out the conversion, e.g. oil pump, alternator, front suspension?"

Opinions will differ, but I'd suggest all three examples you listed above are "optional" unless something is specifically broken or worn out.

Instead of answering your question directly, I'm going to do what I always do anymore and recommend you survey the 100+ "How It Was Done" articles that have appeared in The British V8 Newsletter over the last fourteen years. (You don't need to select one guru or rely on one web forum!) You'll find MANY different approaches, and most of them are right for someone. You can at least read what other people learned from their mistakes... most of the articles include a few frank words on that subject.

Have you been to this webpage: (You can click on the asterisks in the right-hand column to link directly to many of the HIWD articles. Surf around. Other HIWD articles can be downloaded in PDF form on the same website, plus there are many additional MGB conversions shown in the Photo Gallery.

When your conversion is done, don't forget to return the favor by submitting your own How It Was Done article!

My recommendation is , use the Toyota box, Supra or Celica & the Dellow conversion kit with the original diff. for starters. You can always change the diff. later on if you're not satisfied with the result.You've got to modify the trans. crossmember no matter which 'box you use. If you stick with the original diff. the speedo doesn't need recalibrating & from memory the original speedo cable fits the Toyota box. I've been using the original diff. with a Celica box in a GT for 17 years. The final drive ratio is 3.2:1. I also have an MGB V8 roadster with a Ford 8" 3.08 diff. The top gear in this box is 1:1 so the final drive is 3.08. Apart from the fact that the GT is a little quicker off the mark than the Roadster there's not a lot of driving difference between the cars. Try not to use the Toyota slave cylinder if you go this way. If you can use the original slave cylinder, so much the better. Good Luck, Barrie E
Barrie Egerton

Hello T
I'm using a W58 supra box from Jeff. The engine I've got is a 3.9 range rover one. The fifth gear on the box has a ratio of 0.78. I'm using the orrigional diff' and have had no problems at all. Apparently the factory MG diff' was adapted from some sort of Leyland small truck, so good to 220 BHP I'm told.
Most of the engine bits over the many years (heads, fronts etc) are interchangeable. This is how come I'm able to use the '85 rangerover front (that incorporates distributor, waterpump & oilpump) with the '95 motor. The reason why every one uses the '80's front is because you need to use the RV8 pump base. The rangerover and rover pump base incorporates the oil filter attachment. In an MGB this filter base unfortunatly occupies the same space as the steering. The solution is to use the flat RV8 base that has outlets for a remote filter. The later fronts don't have the same removeable/swapable pump base. I bought my RV8 base and remote oil filter from Clive Wheatly (he's on the net) in england for 100 pounds. Quite a few people sell them locally as well (bit more expensive when I bought mine). Triump and rover spares in adelaide, AAAutomotive in adelaide, plus four in dandenong.
The Supra box fits into the tunnel no problem.
The trick is to get the engine as low as possible at the front. This allows you to push the back of the gear box up as high as you can get it, which tilts the heads away from the rear of the engine compartment, which allows you to place the engine as far back as possible, which, in turn, gives you more room for the radiator and fan, plus alot more bonnet clearance than usual (aways an issue). To this end you need to get an SD1 harmonic balancer/bottom pully (they are very cheap at the wrecker). This has a long neck on it that allows the steering rack to tuck in neatly under and allows you to get the motor lower.
You can make your on engine mount brackets easily enough (I did) but it's tedious and time consuming involving lots of trial fitting of the engine and gearbox. Glenn Towery of Towery Foreighn Cars in America (net) makes a set of brackets that set the engine both lower and further back than most. $70 US dollars I believe. Money very well spent as it gives you a flying start. Far back is good with the supra box because the longest gear lever base is just a little shorter than the MGB one. The gear lever base is the D or 21 inch (the longest), you'll need to specify that with Dellow. Try to get the W58 (0.78 final ratio), failing that the W55 gear box (0.82 fifth). Actualy check this when the gear box arrives, he sent me a W55 in error and I had to send it back(he paid for the freight).
The rear gear box mountis easy, cut off the MGB gearbox brackets and slide into the crossmember a cut out section from a peice of three inch box steel. The supra mount has a flat base and attaches with four bolts and a big centre restraining bolt.
See if Dellow will sell you the one and one 16th inch slave set up. This is ideal for MGB's and Gives a travel of about half an inch. You must ask otherwise you'll get the three quater inch supra slave which is hopeless. Way to heavy and over driven with the MGB master cylinder.failing that you can use a one inch range rover slave and a simple adaptor plate which is a chunk of steel with some holes drilled in it.
Get hold of a rover P5 or P6 alternater bracket which are exactly the same as the MGGTV8 of the '70s. They are about $30, unless you ask for an MGV8 one and then you pay $80.
If you get a air conditioner style water pump pully (this is a cast item) then if you spacered the P6 bracket forward 20mm, this will all lined up with the bottom pully. Other wise spacer the existing water pump pully.
Fuel injection? see the archives for detail but if you use a feeder pump (peirburg #12001) that pulls though a large filter and feeds the primary pump then you don't need to bother with altering the fuel tank itself.
If you click on the flags (top LHS corner)this will lead you to the V8 section and in there (down the bottom) is a link to Roger Parkers most excelent write up with lots of photos and V8 conversion stuff)


PS- exhaust- use the RV8 style "through the inner guards" extractors. You get, 10 to 12 more BHP, no over heating problems with the starter motor and no overheating problems (ever) for the engine. AA Automotive in adelaide (Adrian Ackhurst) will sell you the best set I ever saw. Or, buy a stainless set off Clive in England (beware of the 25% tax you pay to get car stuff into the country).
In Australia the alternative "block hugger" (block hugger =block heater!) style headers often cause problems with over heating and unrealiable starter motors.
Radiator- The one you've got has the V8 core and should suffice. The hose outlets are reversed though. To be on the safe side I used an alloy radiator that I got from Race radiators in Dandenong (Melbourne) for about $600. This is about half again as big as the MGB one, and is the prettiest shiniest radiator you'll ever see!
For the electric fan thermostat, I used the existing Range Rover air conditioner thermostat located on the mechanical thermostat housing.
Rover Temperature guage sender, lower resistance than the MGB one. Options are to use the MGB one if it fits (sometimes doesn't) or put a small variable resistor on the wire as I did.
You do not need to use an oil cooler with the V8, unless you just like to look of them. I plumbed one in mostly because it was sitting on the shelf at home.
I used the 100amp alternator that came with the motor. I wired this directly to the battery terminal on the starter motor with the heaver guage wire that was already on the alternator, no problems. The old alternator wire I used to power the electric fan and the fuel injection gear via new fuses.
The MGB slave cylinder hose has the same imperial thread as the One inch range rover one, or the 1&1/16 dellow (which is infact and early Holden Slave).
I found that the supra W58 worked out at about 0.7 of what the speedo was showing. When my speedo showed 70 MPH, I was doing 100 K's per hour. I bought a ratio box and put it on the cable. You will need to get the $30 Dellow speedo cabel angle drive by the way, unless you want your speedo to bounce. This is second hand supra stuff.
Starter motor- In order to fit, you need to use an Rover SD1 starter, this has the solinoid on the bottom, not the side. They are so cheap the wrecker swapped me my rangerover starter for two SD1 starters, I was probably ripped off!

Hi Guys. I am overwhelmed with the response and level of information, wish I had asked earlier instead of stumbling in the dark.
I was trying to avoid cutting into wheel wells for the extractors but I now see that the heat issue also affects other parts of the motor etc.

The motor I have is out of a 83 Range Rover.
Also spoke to Geoff Dellow today and gave me same advise as Barrie mentioned, drive and see how it feels.

Has anyone tried the Adrian Ackhurst engine mounts/ plates, before I rush off and buy from the states.


T Zorzo

Peter, you mention tilting the engine/gearbox so that you "get the engine as low as possible at the front. This allows you to push the back of the gear box up as high as you can get it, which tilts the heads away from the rear of the engine compartment, which allows you to place the engine as far back as possible". Does this mean the engine heads are not level? I've heard this comment before and always assumed the engine should sit horizontal to the ground. Am I wrong?
Mark Mathiesen

Don't know anything about Adrians brackets. Be aware that the further back you set the motor the higher the bonnet is. Obviously the lower you set your motor, the more bonnet clearance you get. Glenn claims that he can fit a fuel injection plenum by machining 16mm off the bottom, and he can fit air conditioning. That's pretty low and far back! Much further than standard. You might ask Adrian how far back from standard his set the motor. Keep in mind the radiator clearance issues with using a standard rangerover water pump (you'll want to keep you standard RR water pump, I promise)

The tranny tunnel just back from under the heater is the low point and problem area. The engine and gear box kind of pivot around this area. Front of engine up, gearbox goes down; gear box up, engine down etc.. I had a go at dressing this area up and gave up, it really is a cut and weld job, and I didn't want to do this.
By using the long neck Rover SD1 balancer you can get the engine front down etc etc. By doing this you are actualy makeing the engine more horizontal to the ground, not less. Often MGB V8 conversions have the motor on a bit of a backward slope. I can't see how it would matter too much, the car's hardly ever dead level anyway. The orrigional MGB GT V8's used a similiar harmonic (long neck) balancer to the SD1. This is the same as the one in the Rover P5/P6 (as was the orrigional water pump etc. The P5/P6 balancers are hard to get, expensive and (if you are using a rangerover front) set the fan belt back a little too far and you get clearance problems with the bottom radiator hose. The V groove is machined into the balancer itself. There is no bolt on pully.
My approach was (Tony might find this useful)to unbolt most of the SD1 balancer pullies and only keep the flat one. I then spacered the alternator bracket forward 20mm to alighn the alternator. I tried two approaches with the water pump. First I spacered the existing pressed metal pump pully forward 10mm by putting a 10mm spacer between the pully and the nose of the pump (needed 3 longer bolts of course). This was fiddly to fit but worked fine. However one day, at a wrecker, I noticed the cast iron variety of water pump pully that located the belt 1cm further forward. I have since seen this pully on a variety of '80's Rovers and range rovers, all with air con'. This I have now substituted. There is no interference problems with the bottom hose (and it's cheap!). I did eventualy have the V in this pully machined about 2mm wider and deeper so I could fit a larger belt, but it ran OK with the narrow belt.
Tony, another reason to set the motor further back than standard (if you are using a range rover front, as I am) is to ovoid using the RV8 water pump. If you weren't aware of it the MG RV8 had a motor straight out of the late '80's, early '90's range rovers, with the exception of the slightly shorter nosed water pump. This item costs the princely sum of 250 POUNDS (!!!) English. This should run you about eight hundred to land it in OZ (don't forget the Tax). This is compared to around $120 Australian dollars for the more commonly availiable range rover longer nosed pump.
These are some of the items under discusion.
(Clive is not the cheapest by miles, but in all fairness his gear is good)

PS (again!)
You can make your own engine steady bar by adapting the existing steady bar that is under the 1800 gearbox. Relocated to across the back of the engine.
You'll note the starter motor (buyer beware!)

Another chance find,
Top radiator hose
Nissan Pintara RWD '86-'89

Grommet GR206
OEM 2150154500
GATES 05-0598

This radiator hose actually fits better than the RV8 one and costs $15. Compared to about $60.
Its longer than the RV8 one which suits my application of radiator far forward and engine far back perfectly. infact I had to cut about one inch off the end.

Thank you for your continued input there is so much info to take in that it will take me a weekend to sift through each item.
I assume that there is little if any local suppliers for the parts that you mention and are shown on the Wheatly link.
T Zorzo

There are heaps of others around, that link just happened to show some photos of balancers, remote pump bases, extractors etc. As well as some very expensive SD1 starter motors and P6 alternator brackets! The only thing you really need to get from overseas are Glenns brackets, but as I say, You can make them yourself if you don't mind spending the time. Standard brackets will cause you grief wrt the Rangerover water pump.
I bought Clives "through the guards" extractors and at the same time got a pump base. These are very well made, stainless steel and include a cross linking section to bring the two pipes into one, right where the 1800 header ends. That makes it easy. However at 550 pounds, less 15%VAT, plus 55% import tax, plus 10% GST, plus about 50 pounds freight; thats around $1700, expensive! I wish now I had got Adrian Akhursts headers. These are around $1200, but mild steel with no cross connect. He will get them ceramicaly coated for cost (around$200) which is better than stainless both from an asthetic point of view (stainless discolours quickly which was a suprise) and from a heat insulation point of view. Adrians headers are also vastly superior, being of a mandrel bent two stage tuned, very wide bore, twin pipe arangment. In other words each works out about the same in cost, but adrians is better. There is a guy up in Northern Victoria who makes a set for around $800, but these are pretty rough in comparison.
If you want the better radiator (it's a good one) you can give Race Radiators in Dandenong a ring and just ask for a V8 conversion MGB radiator, like what he sells to Andrew at MG Workshops. Andrew is a very nice guy who has been doing V8 conversions for years. He'll sell you various bits and pieces way cheaper than Clive (usually). He's not on the net (BIG mistake) but is on the phone
M.G. Workshops 10 Pickering Rd Mulgrave 3170 (03) 9545 0111 Fax (03) 9545 0968

I bought a very nice Brake disk conversion set (adapted from a Volvo)of him.
I would probably be comparing prices from Adrian, Andrew and Neal at Plus four in Dandenong
Plus Four Automotive Services
22 Dingley Ave Dandenong 3175(03) 9791 8025
Neal built a supercharged V8 MGB recently that has to be seen to be believed.
Obviously there must be similiar people in NSW also.
Also if you buy Roger Williams book "How to improve your MGB, MGC and MGV8 (veloce puplishing) there's heaps in that.
And if you haven't already found it

I assume that the range rover fly wheel is out as it may be too heavy, is the alternbative going to rover F/W etc, any idea on cost and who may carry these.Spoke to Adrian Ackhurst to day he wants approx $500 for the oil pump base, seems high? Tried email Glen Wheatly in UK, it bounced bank???

I have twin strongbers on the motor, is it possible to simply machine the piece that they sit on and run a Holly or the like? If so how much material do we remove top and bottom?
Are the gearboxes marked to identify the type of bow 33 or 58
T Zorzo

$500 is expensive, ring a few people. As you can see from clives site, the pump base plus filter base is around 140 pounds, less 17.5% VAT plut 25% (which you might get lucky and not have to pay) plus about 20 pounds to get it here. $413 australian. Try ringing him. There is no real way to ovoid getting one of these, that's why they are pricy.
For the fly wheel, barry in Sydney tells me you need to have half an inch machined of it and new holes drilled and tapped. The range rover one is too thick. Aside from the drop in performace, there would be clearance issues I guess. Ask Dellow.
I bought one from Triumph and rover sparesin adelaide for around $200, which I regret a little. They had used a very coarse tap on the bolt holes that made centreing the pressure plate difficult. You might also get lucky and find a Rover manual flywheel from a sedan. I managed to locate only one, and the fellow wanted $300 for it (he's still got it threes years later, no suprise). Find a local machine shop to do it for you, there should be plenty. Or Jeff dellow might be able to offer something.
My set up is fuel injection and I know know much about carbies. Actualy price this out very carefully before you fit carbies. It may be more expensive than setting up fuel injection. The mod's to the fuel injection air intake only cost about $100 to get done.
You would need to get the manifold, that has the fuel injection gear on it, the intake "hot wire" and the computer. Plus a couple of fuel pumps. Setting this all up is dead easy and people on this site will give you more details than you probably want!

Spoke to Geoff Dellow today, he recalls machining the RR flywheel and fitting the 9 1/12 clutch to it for someone by the name of Barry in the Sydney area approx 2 years ago and appears that it worked well, he is getting back to me.
If Barry reads this and it refers to him would you mind dropping a line.
Did you upgrade the front suspension if so what to/how.
I have just set up a volvo caliper and peugot rotor front disc brake upgarde will give you feedback once i get the car on the road, looks to work OK on the bench.

T Zorzo

I don't know if I'm the Barrie in question or not. I had an RR flywheel machined & re tapped to take a Ford Falcon press. plate. but it was 17 years ago. The Ford Press plate was about a 1/3 the cost of a Rover one. I had the flywheel machined to the same specs as the original MGB V8 one. They are in the MGB V8 maint man. supplement. I'll scan & send you a copy if you want. You can have the original Rover manifold machined & have a Holley adaptor plate welded to it. I also did this 17 years ago & it's still on the car. I did have to settle for a 2 barrel carby though. A Holley 350cmf I've been told that a 4 barrel carb can be made to fit but I have my doubts. I believe the 4 Wheel Drive Centre at Taren Point Sydney will do the manifold mods & maybe the flywheel too. Apparently the manifold quite common amongst the Rover fraternity. The Rover Car Club may be able to help. The people who did my maching are no longer in business. Barrie E
Barrie Egerton

Thank you for your reply.
Yes thank you on the Maint manual for the specs as I have a local machine shop who did the calipers for me. If you send the scan through to my private email
Any idea on how much was machined of the manifold to make it work?
T Zorzo

That should read DONT know about carbies.
Yes Barrie, you were the variety of Barrie refered to (at least by me)
Tony, thats about the ideal brake set up for value for money I think. If you havn't already got them you can get the brake hoses from Andrew at MG work shops. These are braided stainless with volvo/mgb ends and (this is the really important part) have an ADR number on them. This makes the brake mod's legal. In Victoria at least they get weird about brake mod's. In order to be legal you must have the orrigional rubber hoses (not braided), even if they are inferior! (OR have hoses with a magical ADR number on them). It'll be no suprise to learn that they are around $180 the set.
On the subject of engineers, they like to see a clearance of about 1cm between moving parts and other bits. This gets a bit close in the tunnel, which reminds me that the MGB gear lever hole is off set about half an inch to the left (this came as an unpleasant suprise to me, I'd never noticed). Don't be tempted to centre the gear lever there and have the engine gear box at an angle, engineers don't like it. Infact I do have a few mm offset to the left in order to clear the handbrake bolt but it's hard to tell.
I keep recomending Towerys brackets. I should add that I have not seen these. I have read on this site what I know about them and since the objective is to get away from standard brackets (unless don't mind buying expensive water pumps) they seem to be a good bet. If you make up your own (as you sound quite capable of doing) then the objective is to locate the rubber mounts(that they attach to) as high up and as close to the motor as possible. Bolt a longish piece (about 20cm by 7cm) of 5mm steel to the bracket mounting holes on the block and weld another bit of steel on at the same angle as the body brackets (so they are parrallel). Kind of like an opened out or slightly flattened bit of angle iron. I also welded on tiangular reinforcing bits to the ends, which may not have been necessary. The rubber mounts on mine ended up forward of the formost engine block bolt, the bracket goes right to the front of the block.

I am not race car driver, pure amaturesville, but I have read in a variety of places, that the best approach with MGB's is to stiffen up the front , alot, and leave the back springs soft, even take off the rear antisway bar, if you have one. The ideal is that the stiff font end controls roll while the rear live axle is free to move and follow the road surface. This maintains the maximum amount of rubber , and grip, on the road. This makes sence and seems to work for me. I lowered the car back to chrome bumper height and used uprated and (obviously) lowered front springs that I got from MG workshops for $110. I fitted the largest antisway bar on the front that I could get. seven eigths if memory serves. I would go thicker if I could find one.
I did nothing else to the front other than use poly ethylene bushes. I used the Blue, or softest grade, and I found them a big improvement. You can go two grades harder, but unless you intend the car for track use I would not recommend it. Blue worked out to be firmer than the rubber, but actualy less harsh. Less crash and rattle going on.
You can spend heaps on air shocker set ups, forntline costello (internet) for example. However money was an issue for me and I quite like the very MG idiosyncratic armstrong shockers. I also couldn't see value in changing. Keep in mind that the car will end up about 30kg lighter at the front.
At the rear I (obviously) lowered back to chrome bumper height by using one inch blocks and shifting the hole for the front of the spring up about 45mm. I kept the orrigional springs. If you lower the ride height (or I like to say "restore it to what it should be"!) you also need to cut an inch off the bump stops. Takes about 5 minutes to do. With out enough suspension travel you get over steer issues.
I am actualy going to do radical things to the rear the moment my icy cold garage warms up a bit. I intend to fit coil springs, a panhard rod and a trailing three arm link arangement. I'll replace the leaf springs with two trailing arms (probably from a toyota tercel) and fit a single arm on top of the diff'. Three link trailing arm set ups are being used on the current mustang and were used on the first Jag' C types. The MGB could almost have been designed for an upper middle trailing arm, plenty of room and an ideal mounting point at the top of the tranny tunnel. This should cost less than $1000 to do, I figure.
Whatever you decide to do you will find a need to stabilize the rear axle which is inclined to "wind up" with all that power going though it. The problem is that you need the softer springs for the grip at the rear, but you can't really aford to have soft flexible springs when you push 180 odd BHP though them. They solved this (or rather, copied from others)on the RV8 by fitting "antitramp" or "antiwindup" bars under the springs. Basically two trailing arms in addition to the existing spring.
I figure that if I uses a third middle arm and a coil spring I can achieve a better effect with far less unspring weight.
But really the skys the limit on what you can spend on suspension.

OR spend no money alt all:
Other than the height, currently my rear suspension is as orrigional. I usually take off from stationary in second gear (heaps of accelleration) However I take care not to accellerate hard in first gear, too much unnerving crashing/thrashing around going on back there.

That should be polyurethane bushes not poly ethylene!
Actualy of Australian invention and Manufacture.

I don't know of any markings ans would be suspicious of them anyway.
Dellow takes the boxes apart and reco's them. In reality these things are so strong I suspect he just inspects and replaces the gaskets . I am given to understand (ie not sure) that he assembles them as per d size lever, gear ratios etc.
The only sure way is to put it in fifth gear and turn the input (clutch plate) shaft alleast ten times while counting the revolutions of the tail shaft. 100turns at the front will get you 78 at the back or variation on theme. The w55 gets you 82

Peter or Barrie
Any idea on what EFI gear would be $$ in the market place. I am waiting on a call tomorrow from a guy who is stripping a Rover SD1 1985? What part should I look to grab?
You guys are absolute endless source of info and more importantly source sites etc, and what works.
T Zorzo

" I intend to fit coil springs, a panhard rod and a trailing three arm link arangement. I'll replace the leaf springs with two trailing arms (probably from a toyota tercel) and fit a single arm on top of the diff'. Three link trailing arm set ups are being used on the current mustang and were used on the first Jag' C types. The MGB could almost have been designed for an upper middle trailing arm, plenty of room and an ideal mounting point at the top of the tranny tunnel. "

Great plan!

We've been kicking that idea around for a number of years. A good friend mine finally did it. Need better pics, though.
Carl Floyd

The factory V8 diff is 3.07:1
The original 1800 diff will make first gear virtually redundant and cruising at 70mph the engine will revving far too high to be comfortable.

I am using a 5 speed LT77 gearbox mated to a 10.5:1 3.5 litre Rover V8 for my own conversion.
I plan to use a factory V8 back axle.

One option that you may like to consider, is to have the 1800 case milled out to accept the V8 crown wheel and pinion.

Just a thought.


I've been quoted about $1800 for an EFI setup a couple of times. I don't think the '85 SD1 had a "hot wire" system. I would advise not to use anything else unless you go for an aftermarket system which will cost a lot more. Barrie E
Barrie Egerton

Hey Carl, good to know. Do you also know the details of the coil over shockers? It would be great to be able to be able to pick up the phone and just order up a X type shocker with a Y type spring.

Diff ratio- I really enjoy the zippy acceleration of the 3.9 diff. The low first is good for crawling along in peak hour, and around car parks. I can accelerate strongly from stationary to 70Ks in second gear, which is also fun. Fifth is about 27hundred RPM at 100KPH, which is right where the power curve starts to flatten out and the motor is operating most efficiently. However everyone has different personal likes and dislikes and this site has some more than usually individual persons posting! I built my own car and I did it MY way is the motto.
Barries got a point, price out the carbie route and then keep that in mind when looking around for efi. EFI won't necessarily get you more power but it is allot cheaper to run (more efficient) so thats something to factor in to the cost of it. Also factor in the price of the 2 fuel pumps (youll need a feeder pump as well as the main one), about $250 total.
Its also easier to set up I believe. No messing around with different jets etc and of course starts instantly every time. Mind you Ill freely admit that the big chrome air filter on carbies does have a certain amount of style to it.
I payed $2300 for a motor with 20,000K on it and got all the efi gear. That was quite a good price, but not that good, so $1800 is for mugs. As Barrie says, you could probably set up a MOTEC or something like for that.
I would guestimate less than $1000. Allot less if you can find someone who's blown their 3.9 and just wants to get rid of it. The bits just bolt straight onto 3.5s.
Useful things to know about Range rover EFI if you are hunting around for a cheap one:
There were three stages.
Stage one- the federal or "flapper style". This was an analogue electronic system that used a balanced spring loaded flap/paddle on the intake that was pushed backward a distance depending on how much air was flowing into the engine. The air intake manifold on the engine was two piece arrangement with the upper bit (plenum) a cast flat topped affair that had 8 bolts holding it to the manifold in the valley that connects to both heads. This may be made to fit under the MGB bonnet by machining however much room you need straight off the bottom of the top bit of the manifold (that has the throttle mechanism on it).
Stage two- Same electronics but the manifold changed to the later "Hot wire" style. This has three sections to it. A top cover (with the throttle mechanism), this covers a trumpet tray that bolts to the valley manifold. This set up is taller than the stage one EFI and has 8 trumpets of various lengths (in its trumpet tray) to even out the air passages to the cylinders. This manifold flows much more air much more efficiently than the previous manifold. More power. The top cover has a number of "stripes" caste into it and is not dead flat, has a slight bend in the middle. Has 6 Alan key style recessed bolts holding it to the trumpet tray. This was used from at least the mid '80s (or earlier) onward on Range rovers.
Stage three-Hot wire EFI. They changed the electronics to digital and used a heated wire to measure air flow. Infact two wires, one heated and the other not; then measure the difference in resistance. Obviously the in coming air cools the wire. A very simple Wheatstone bridge set up. This set up is much more efficient than the older style which also had problems with reliability. Also if you got a backfire with the flapper style you usually damaged the flap pretty badly.
The computer box for the hot wire is allot smaller, very roughly 15cm by10 by 3cm. Usually painted black. The computer can be switched to "non catalytic converter" mode by changing an external plug in resistor. The flapper style is about half again as big and not painted.
The essential differences between mark 2 and 3 are the computer, the air intake meter and the fuel rail and the idle control stepper motor" on the back of the manifold. Also the temperature sensors for the fuel and water and the throttle sensor. These all plug or bolt into the older stage two manifold. The injectors are the same. This interchange ability means the Hot wire is more expensive and way more in demand than the Flapper (or federal) set up.
The stage 2 & 3 manifolds may be made to fit under MGB bonnets by having the vacuum take offs on the trumpet tray welded up and having machined what you want off the top and bottom of the tray. You can get up to 28mm this way. You can get an additional 5 to 7 mm more off the top cover if absolutely necessary.
I got the shop to take 25mm off altogether. This fits with about 4-5mm bonnet clearance. Keep in mind my motor sits further back and lower than usual. They charged me $100, but that included machining the water pump pulley groove lager as well. Engine Improvements opposite the St.Kilda Town hall.


Also- Wireing into the MGB- You need a wire to power the computer, a wire off the ignition and a couple of wires to the coil. That's it!
The rest of the loom is completly independant. The Hot wire loom even has a bulkhead rubber plug the same size as the MGB one!

er opps, W58 gear box, 78 turns at the FRONT will get you 100 at the back. It's an over drive.

ps about 1989 the Hot Wire appeared in RR's

Speaking of a 3-link rear axle setup, Carl Floyd wrote: "We've been kicking that idea around for a number of years. A good friend mine finally did it. Need better pics, though."

Ted Lathrop, of Fast cars, Inc, has just completed a 3-link installation in an MGB, and is preparing to put the same setup in my own MGBV8 (Ted talked me out of using the JAG IRS in favor of the 3-link). I took photos of it a few weeks ago and posted them on my Advance Atuo-wire web site, at The project wasn't completed when I took the photos, and he's made some changes since then, but these photos give a godd idea of what it's about. Check 'em out!
Dan Masters


as far as cheap EFI is concerned, as previously noted, the hot wire system 1989-1995(?) is ideal.

On E-bay in the last week, the manifold base is $20.00(USD), the trumpet section $20.00, plenham with IAD and throttle linkage & butterfly $50.00, hot wire/air flow sensor $20.00, 14CUX computer $50.00. Only thing not cheap was the wiring harness at $150.00. All of this was from various sellers. Fuel rail was $15.00, no injectors listed, but I have bought a low milage set for $60.00 in the past. I also bought a complete harness for $40.00. You will need a cone shaped K &N air filter for $60.00 new, and a rubber elbow to connect the air sensor to the plenham. I used a piece from a late 80's GM 4 cyl at $3.00 from a local salvage yard. You need a long accelerator cable- I used a hand brake cable from a bicycle shop $8.00.

Electrical hook up is 1 wire to constant hot, several ground connections, and 1 wire to the coil.
Jim Stuart

I'm looking at the future Dan! Many thanks.
Almost exactly how I imagined, except the panhard was on the back.

Dan, are you able to tell me the details of those coil over shocks? Who makes them and what is the ratings on the springs etc. I'd like to be able to order up a set. My (preliminary) enquiries localy have not been sucessful. $1200 each was the best I could do and they can keep them at that price!
By the way they might be better up the other way I think. Less unsprung weight, or do they have to be that way up?
My current thinking is to set up the middle trailing arm offet a little to to the RHS. They did this on the early C type jag, and they are setting them up like that on the cobras. Mind you the cobras aren't as well suited to an upper middle arm as MGB's. Not as much room so they have to use an elaborate bracket to offset backwards.
For the benefit of others, the idea of this off set is that this compensates for the driveshaft reaction that lifts the RHS wheel a little. I believe that the formula is the tan of the wheel diameter, about four inches idealy. Because of the battery box, I won't able to get all that, but I figure even two inches will help. Also I've read that if the front of the middle arm slopes downward a little you can eliminate squat & hop on accelleration. Abount an inch down at the front was the figure mentioned. I'll keep the panhard rod at the back of the diff' and put the coil overs (if I can get them) on the existing shocker bolts (pure lazyness!) If I can't get the coilovers I'll get some springs made an put them into the bumpstop locations (and keep the armstrongs).

"except the panhard was on the back."

Like this? I also prefer how the straight Panhard rod on Martyn's car (built by Larry Ellis) mounts to the axle with bolts in double-shear instead of single-shear, and how all his links have a hexagonal section so you can get a wrench on them when you're tightening up jam-nuts.

Ooooh but that lightweight Currie axle and those Wilwood brakes... now that's nice!

Barrie or Peter

Spoke to Dellow today and before he starts machining the flywheel I need to know the weight of the original v8 fly wheel. Any help?
I assume that the 1/2inch was taken from the rear of the f/w can you expand on this. Jeff Dellow could'nt find his original template that he used originaly.
How has retaing the R/R flywheel affected performance both bottom and high end.
Without pulling my clutch master cylinder apart does any one uhe the bore size/ diameter
T Zorzo

Thanks for the pics, Dan. That looks sweeeet I would love to test drive Ted's new 3-link!
Carl Floyd

Neat set up Curtis, looks like it bolts directly to the end of the axle, long as possible, and strong.

Half an inch of the face Tony.
Here's what Glenn had to say back in 2003
Glenn Towery, Dover De. U.S.A.,
Scott,I have been told that the buick fly. should not be turned more than 5,500 r.p.m. I turn the rover, T.R.8 6,000 - 7,000 I lighten the 8 wheel by looking at the face of the wheel & the ring gear & thin I cut 1/2 of the distance off the face (.200 to .300 off) thin I cut the back of the wheel from the ring gear straight down. DO NOT cut to far down were the bolts holes are or it will get to thin, with the machine work on the face side of the wheel. I have run a 33 lbs. wheel , a 20 lbs. wheel & a alu 12 lbs. the lighter thay got the faster it hit the r.p.m..I can get a good ring gear for you if you need.

The archives contain heaps more info'
If you weren't aware of how to access these go back to the main page
up the top there is ARCHIVE just above "last updated"
Sign youself in (doesn't cost anything except a few anoying emails from some guy in Africa trying to trick you into giving him your bank account details "You have won first prize..or let me put $100000 in your account.. etc etc.."). Not as fast as a direct question, but if no one answers it'll get you there eventualy. The search find doesn't work too well so you'll need to scroll down to F for flywheel.


I seem to recall seeing this cast on the outside of the cylinder. I believe it is three quaters of an inch. The MGB slave is one and a half inches. The orrigional V8's used a midget 1 inch slave. These slaves are hard to get, which is why I used a one inch rangerover slave, which has the same thread as the MGB one. I made up a bracket/adapter plate to fit it. I didn't know at the time of purchase that Dellow does a one and one sixteen slave, if I had know, obviously I would have tried that. Still a little anoyed that he didn't tell me!
Using a rover pressure plate, you need a travel of just a little over half an inch at the slave. With my set up it feels that the clutch is completely disengaged with just a little over four fifths of the pedal travel. Obviously to minimumize the effort, you want to have the most pedel travel you can get.

ps the 1" rangerover slave is the older steel slave. The newer ones are 3/4" alloy

EFI: Don't overlook the MegaSquirt EFI controller ( It will work perfectly with the Rover hard parts and sensors and although it may cost a bit more than junkyard and ebay parts it gives much better tunability and is constantly being improved. The current beta version can run a missing tooth crank trigger multi-coil ignition as well as the efi and has such things as the ability to modify timing advance based on inlet air temperature, a very useful feature for getting the most out of your engine regardless of whether it is hot or cold out on any given day. It can be tuned on the fly using 3D maps for mixture and timing, and with a wideband O2 sensor and knock sensor can be set up to self tune. What all this means is that you can make performance improvements to the engine and tune the ignition and efi to match closely. If you have access to a dyno you can get it as finely tuned as is possible. I've been running MS on two vehicles now for about 5 years. I met the developers shortly after they initially released the v-1.0 board about a dozen years ago. It was an impressive accomplishment then, and since then they have truely demonstrated what open source development is capable of when carried out properly. In forecasting things to come I would say that the day is not far off when the system will become completely self tuning, using the available sensors plus accellerometers to optimize performance and economy. I don't know of a single system available anywhere at anything approaching the economy of the MS that can come close to doing what it does, and it is only going to get better.

Axles: Ted Lathrop is almost obsessive about reducing unsprung weight. The 8" Ford axle he likes with the aluminum carrier appears to be considerably lighter than the stock MGB axle. He has obviously gone to a good bit of trouble to design a rear suspension that will compliment his IFS system, and the result looks very good indeed. Probably a little overbuilt as he tends to lean that direction rather than the other way at least initially, the one that goes in Dan Master's car will be improved in subtle ways. After that he may very well find ways to simplify installation with the goal of eventually offering a bolt-in package but that may not be achievable with the desired strength. He does phenomenal work though, and has a proven track record as far as many of us involved in these conversions are concerned.

Jim Blackwood


<The 8" Ford axle he likes with the aluminum carrier appears to be considerably lighter than the stock MGB axle>

Do you know which year and model Fords came with an 8" rearend with aluminum carrier?

Phil O

You don't need an oscilliscope, just adjust the pot to to half of what the tacho initially shows
Clever man that Zac

"Do you know which year and model Fords came with an 8" rearend with aluminum carrier?"

None. That is a $400 aftermarket gear case.
Carl Floyd

Currie aluminum gear case for 8" Ford:

It's pretty sexy, but I dislike how their catalog neglects to tell you how much lighter it is than the iron gear case, which they also sell ($60 for a "good used" OEM gear case as shown here

Sorry to hijack this thread for a momemt but I would be interested in any comments from my Oz colleagues on the performance (or lack thereof) of one Adrian Akhurst of AA Automotive in Adelaide. His name was mentioned in an earlier posting. I placed an order with said Mr Akhurst for a sports exhaust system for my V8 in April/May. I'm still waiting. Despite several phone calls / emails, all I have got so far are lame excuses and vague promises of delivery in "a couple of weeks". Never once has Mr Akhurst bothered to contact me to inform me as to what was happening with my order. Frankly, I have had enough of being jerked about. Should I persevere with this man or should I give him the flick and go elsewhere? Can anyone recommend a RELIABLE supplier of sports exhaust systems in the eastern states? Thanks. Tony

Headers or the whole system?
If he is not keeping at least one set on the shelf then keep in mind that he doesn't personally make up these headers and Adelaide is not a large city, big town really. Just a thought.
Do call and tell him that you now have a deadline, it'll either hurry him up or leave you free to go elsewhere.
There's no one else in Australia really, and not knowing about Adrian I went to Clive wheatley in England for my headers.
If you are just after the exhaust part then just drive yourself to any of a multitude of exhaust places.

That's OK. I am interested in your comments as I will also be looking for extractors etc at some stage. My own experience with AA was only as late as last week, I ordered engine support plates and engine mounts, no problems received them within a week of ordering, I did make a call simply as a follow up 4 days afer payment simply to confirm receipt of postal address.
Did you go the way of block huggers or throught the wheel well. I am interested in knowing what you have done with your car etc. Where abouts in the eastern states are you located?
T Zorzo

Tony, the "MG Centre of Sydney" in Granville sells the block hugger type. Apart from that,I know nothing more about them. Barrie E
Barrie Egerton

This thread was discussed between 10/09/2006 and 23/09/2006

MG MGB GT V8 Factory Originals Technical index

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