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MG MGB GT V8 Factory Originals Technical - MGB Upgrades - Good deal or not?

Hi all,

Have been dipping into this site for some time now. I have a 67 mgb roadster which although the bodywork is excellent, the mechanicals need some tlc. I am considering various options, whther to go V8, VVC or upgrade a standard unit.

I have taken some advice and it has been suggested that the following would be suitable.

1800cc, lightened & balanced, mild road cam & Stage II head work with tubular manifold & sports exhaust. Electronic ignition, electric fan, K&N air filters and alternator.

Strip & rebuild gearbox. New clutch, hoses, water pump, spots coil, distributor.

Servo brakes & master cylinder, braided flexible hoses, Brembo discs & V* EBC pads.

Updraded front & rear bushes to PU and stiffer anti roll bar & mounts. Upgrade leaf springs. Change tyres to 185 70 R14s.

I plan to use the car for occasional long trips, over to France, blasts in the country etc. Needs to be driveable. No plans for racing/track days.

Any thoughts would be appreciated. Have been quotes about 7.5k for all of this by Maidstone Sports Cars. Seems a bit steep but it is the first quote I have had.


D J L Moore

DJL, you should get a goodly number of responses to this. In fact it is an item of discussion that comes up regularly so it'd be good to check the archives.

It has been repeatedly shown that for the cost of rebuild and upgrade of the 1800 for a higher power level, a good Rover engine can be installed. Perhaps a new one, I'm not sure of the cost of a crate motor over there. And, the maximum HP rebuild of the 1800 will only get you in the ballpark of what a low performance 3.9 will give you, nowhere near the torque and smoothness and very little capacity for power increases. Talking average torque and HP here, not peak. After all, a flat powerband is more useful most of the time. And there's plenty of room to upgrade the V8. Go with a bone stock 4.6L and you have all the power you'll ever need, with none of the usual performance issues such as shortened life, driveability, constant tuning, etc. In fact, it'll be so understressed in the MGB that you may never have to replace it.

And then you get into the issue of driveability. Consider this: On that long pass where you have the revs at max, foot on the floor, and sweating bullets because of oncoming traffic, wouldn't it be nice to still have half or three quarters of the throttle left to use? And on the steep uphill grade where you're not quite sure whether it should be in second or third because neither feels particularly comfortable, wouldn't it be nice to be in top gear with plenty of reserve? That's what you change when you go V-8, and not much else at all. Except for bragging rights that is.

Jim Blackwood

You will not get more balanced advice than Jim's above - I have been down the road with an 1800 as you suggest in your post - several times and back in the good old days got 120BHP on 5* petrol from a highly modded 3 bearing and although the performance was quite satisfying in 1968, it is inadequate alongside the average lightweight modern hatch. I would go with Jim's advice everytime with the proviso that with petrol prices approaching $7 an English gallon and set to rise to $10 within the life of the conversion - I would fit fuel injection - it is much less thirsty in heavy traffic.
FWIW Roger

I think that either way would be good, but like Jim think you'd be happier with the V8 unless you really like the challange of driving a 4 up to its potential. I would advise upgrading to a 5 speed transmission if you keep the 1800, cost about the same as a rebuild on your original box, with the V8 you'd install a 5 speed anyway.
Bill Young

Take Jim's advice. If you decide that you do not want a V8, then look at the great engines you have available to you in Europe, mnay four cylinders with high torque #'s that would fit in your B such as the Granada MKII, Saab 16 valve engine factory turbo or normally aspireted, very compact,Opel, Lancer turbo (mitsubishi)Very compact.
You have plenty of support for the Saab in Europe
Abbot racing,Jam Saab, Bristol. You have engines that we do not get in the USA and have potential for swaps in B if you decide on a four cylinder.
Bill Guzman


Developments have taken place on the uogrades. Have had a good chat with Chris at Octarine, a guy who certainly knows his stuff, and is very keen to share his knowledge.

The plan is as follows:-

1868cc u/l engine, Piper 270 cam (tba) & Stage II head. Fully balanced inc flywheel, fuel pump, plugs etc
New SU carbs with larger needles and K&N filter
New standard exhaust & tubular manifold
Recon gearbox with o/d
Polybushes all round, uprated front roll bar
4 tyres - ? Avon SV3 195/70 R14
New discs and EBC greenstuff pads

I feel this will retain the original character of the car, won't break the bank, and will ensure it is fun to drive bith in our country lanes and on longer jaunts abroad.
D J L Moore

He does not know to much. If he wants you spend your Pounds in a MGB 1.8
It will break the bank later.

This is just my two cents: if you're going to pay someone else to do 100% of the work, you might as well just BUY a car (new or used).

Seriously. Trade that '67 on something that you can test drive, and you'll know better what you're getting.

For me, the real beauty of MGBs is that they're both fun and easy to work on. Sure, they're great aesthetically, but I honestly think SOME people who post on this board would be better off with Miatas (MX5s), or Honda S2000s, or RV8's, or whatever. I mean, if you're not going to enjoy building, or tuning, or maintaining the car yourself - buy a car that's more of an "appliance". Your life will be so much simpler.

That mechanically tired '67 roadster would make such a delightful PROJECT for someone like me (a hotrodder), or someone unlike me that really enjoys restorations. Why condemn it to the boring middle ground?

Over here $20,000 Australian dollars will easily get you a first rate, just like new, you don't have to lift a finger, MOTEC, turn key conversion. The exchange rate is around 2.5. I get the impression that competition is a bit more keen over there, so can be got for less.
Do go for a drive in an V8 MGB, one drive will convince you.

Have given a lot of thought to the options and whilst it would be nice to retain the original spec exactly as it is, I dont want to treat the car as a museum piece. Frankly, improvements such as electronic ignition and the like would have eventually been added to the car had it been further developed by the manufacturer.

Views seem to be fairly polarised between V8 and bog standard, and there is a view that says why change it at all if the changes dont turn the MG into a V8 muscle car.

That I think would completely change the character of the car, and whilst some have said you might as well buy an Mx5 or Honda S2000 I do think that is missing the point somewhat. If I wanted V8 performance I would probably go for a TVR or suchlike. I've owned much quicker cars, some fast Audis and a Lotus Elise. As a pre 72 there is no road tax to pay, and it only costs about 120 a year to insure for both of us (age 35 & 28) fully comp and unlimited mileage!!

The beauty of the MG is that is will not depreciate if looked after, the bodywork is absolutely prisine and again will not cost a lot to maintain if looked after. The main running gear and electrics will be pretty much new or reconditioned.

The MG is there for sunny days, and the improvements will help with a bit of extra oomph for overtaking, having fun in country lanes and keeping up with friends who have more modern cars.

D J L Moore

I speak from some experience having owned a V8 for over 30 years.

During this time I has also owned 4 cylinder MGs including MGAs & MGBs.

I would recommend that you drive one or two V8s before you make up your mind.

If you want "the original MG experience" then an MGA roadster may be for you.

For me a 200 + bhp V8 with lots of torque does the trick, and has done so for many years.

If you go V8 buy a new cross bolted engine; I would suggest 4,600 cc; and use the Rover R380 box.

Good luck
Nigel Steward

I can't disagree with your choice. There is nothing wrong with a well tuned MGB, and while they admittedly don't have the poke of a modern car, they can maintain a high average speed over the long haul on trips and keep up with other cars quite handily.

I understand the urge for people to upgrade their power, keeping the now antiquated chassis because they enjoy the aesthetics of the old MGs, rather than just buying a newer faster car.

I also understand those who prefer to just improve on what the cars came with in the first place. Neither approach is right or wrong and you seem to have found a plan that appeals to you. Enjoy!!
Bill Spohn

I think you should keep an open mind about the V8 swap, at least until you have driven one. Surely someone on this board can give this man a ride?

Perhaps I wasn't quite clear. The only thing changed when you do the swap is the amount of power you have available. It does *not* change the character of the car one whit. It's still the same car we always knew and loved. It handles the same, it rides the same, and it feels the same. With a mildly tuned engine it is more "driveable" than ever before due to the extra torque available at all engine speeds. You never have a worry about stalling the engine, gear selection is much more forgiving, you don't have to downshift to accellerate, and it lopes along contentedly at any speed you like. Admittedly there is more power on hand but that does *not* make it a hot rod. In fact, weren't you just saying you wanted more power?

But what you are considering will most definitely change the character of the car. You sir, are contemplating the building of a hot rod. With the engine mods you are looking at, driveability is going to go right down the drain. Those big carbs are going to make it behave badly off idle and the cam will contribute to that. To get the power you want you'll have to wind it way up, so I hope you are comfortable in the 6000-7000 range because you will be there any time you need maximum output, and that will happen every time you go to pass. Your gear selection may well become much more critical than it now is, and your gas mileage is going to go down. In short, unless you particularly enjoy maxed out white knuckle screaming down a twisty mountain road doing everything in your and the car's power to go as fast as possible, (and then perhaps getting passed by a V8-MGB just loping along enjoying the scenery) simply because you like a challenge, then go ahead and build that little screaming mee-mee. But if not you won't like it as well as the stock engine most of the time.

And just let me say too, that if the above scenario *is* what you want to do with the car, the V8 is still a better ride. It doesn't have to be a snorting, fire breathing monster, in fact almost every one I've seen is quite docile, even more so that with the 4L, but if a fire breathing monster is what you want, it becomes easily and cheaply available too.

Jim Blackwood

Dear DJL,

When we had our first child we immediately grew out of my Austin Healey Sprite, and I thought naturaly I would upgrade to an 1800 'B' with similar mods to your plan.

However projects always take longer than you think and a ride in Terry Pigot's 4.6 Roadster, made me decide to drop the 'middle step' and go straight from 1300 Sprite, 3.5L B GT missing 1800 B on the way.
I am totally satisfied we did the right thing. It sounds corny but the pleasure of a V8 starts when you turn the key.

I would store your Roadster for a year, buy a running V8 in the 6-8 range and drive it for 2006. At the end of the year you can decide which car to keep, upgrade etc.. the beauty is that you won't have spent much money or time. The V8 will still be worth exactlky what you paid for it.

Regards James
J E G Eastwood 1

think James is right.
I have both cars, a 1973 V8 and a 1800 roadster with upgraded engine.
You do not need to pay the price that is aked for a V8 today for upgrading a 4 cylinder MGB! I have done this and would NOT do it a second time.
Go for a test drive with a V8 and you will learn how relaxed driving in a MGB can be.
Even with all the nice Weber carbs, MSX crossflow head,
fast road cam and stage 'x' tuning, you will never have a car that performs so nice and is so satisfying over all like the MGB with V8 engine.
Try a V8 for 2006, there is nothing wrong with this idea and keep the roadster just for fun.
Good luck
... and keep us posted...

This thread was discussed between 07/02/2006 and 09/02/2006

MG MGB GT V8 Factory Originals Technical index

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