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MG MGB GT V8 Factory Originals Technical - market value of V6 vs. V8

Trying to decide whether to buy or build a V8 or V6 conversion. There's a nice V6 conversion for sale locally but the owner wants way to much for it I think. Can anyone in the know opine on values of

other V8s
Olds LA1 3.4L V6s
other V6s

Assume that body-wise the car's been immaculately restored and the conversion has been properly sorted. Also, would a fuel-injected car be more or less valuable than a good old carbureted one?
Bill C.

This all depends on the person purchasing it, i would think. Anyone who cannot get the idea out of there head that 6 is faster then 4 and 8 is faster then 6 would probably take the 8 due to lack of education. Sometimes one is faster then the other, all depends on the way you build it in the end.
"Horse power costs, how much do you want to pay?"
I think that the 302 V8 is more intense in the conversion since no one has a kit for it yet and the BOP/R can be more expensive for the same power that the GM 60 degree can offer. The BOP/R can be punched out further then the current GM 60 degree V6, but the 2005 model engine will be a 3.9L built out of the same basic block, just like the 4.2L is built out of the 3.5L.
The Ford and Chevy are still being produced- Ford I believe in crate motor only, Chevy in crate and production vehicles and will be far past 2005 if the motor is half as good as the units produced in teh past. I do not remember if the Land Rover still has this driveline or one that will fit. Anyone know?

I use the L32 V6 for the majority of my conversions, thats a 3.4L SFI/DIS unit out of the 1993-1995 Camaro, same as the LA1 without the aluminium heads. A V6 should cost less if you compare apples to apples, but it all depends on how hard you look. People on ths board have argued pros and cons of everything.

It always costs more to build then to purchase someone elses, so if you have the money to put down up front, consider purchasing someone elses finished project. Beware of basket cases. I believe that the initial V6 projects that i used to see on the web including eBay were pretty bad and i felt needed sorting out, thus the value was low and the opinion was based off this as well. As tim goes along and more people use the same engines over and over, the conversions get better as info is spread- same goes for the 302 i would imagine.

When considering building it yourself, most people gather parts as they go and spend a winter doing just the driveline conversion on any of the drivelines out there.

Your original Question: Hard to answer. A Ford V8 if done perfectly would be really neat, but some might not like all that engine up there, and teh weight! A BOP with the headers (like the ford) out the sides might look ugly, shoe horned in place and just not natural. A V6, since the GM units were not around until 1980 might not fit with the nastalgia of the age, unless you are building a 1980 MG B like i am, but then again, i am using a 1995 motor, same basic look, but better with the Fuel injection. Anyways, any one of them is going to have its positives and negatives. I would not mind trying a Saturn engine in one as they are all aluminium, bullet proof and very quick engines.

If you have not heard of it, check out the British V8 website and for the V6 conversions, there is a forum just for that at

BTW: I am not sure if you are on the V6mgb forums, but there are two people listed ou ton teh member list as in PA as well.

My answers are obviously heavily bias, so please take them as such.
Safety Fastest,
BMC Brian McCullough

I think Brian gave a pretty well balanced perspective and it's pretty accurate for the majority of cases. There will always be the odd case such as an especially good deal on an acceptable engine and/or drivetrain maybe on ebay or locally that can often be the determining factor whether it should or not. Basically you have to decide how *you* want to balance the factors of power, nostalgia, pseudo originality, weight(not a very large factor IMO), size, complexity, cost, etc. In my (extreme) case, I had even more factors which prevailed: but this is a good example of how far this exercise can be taken. Many equally good examples abound, most of which are hard to tell from an original MGB. The best approach is to decide exactly what it is that you want and then buy or build it. Towards this end the best possible thing you can do is attend the next MGB-V8 meet, where you will have the chance to beg rides in the cars you like the looks of. You won't have to beg very hard. These owners are proud of their work and looking for a chance to show it off. Many will let you drive.

Jim Blackwood

One factor to consider is the choice of other components along with the engine. You're usually ahead in value if the transmission either is matched to the engine or one of several established adaptations for which there are parts and information available. Also the rear axle selection is important, is it strong enough to handle the additional horsepower and torque of the engine. I've seen several engine swaps where the workmanship was beautiful, but the component selection made for a car that was fragile and hard to repair. All the other systems need to be able to handle the increases in capacity a larger engine will impose on them. Cooling, braking, and suspension will all need upgrades. I wouldn't consider a car without upgrades in these areas also, as it won't be enjoyable to drive if you are constantly over heating, having to drive so carefully that you can't enjoy the experience, or bottoming out on every expansion joint.
Bill Young

If you go to the website Brian mentioned above you can view my car in the general section under V6 pics, email me for a price!
Bryan Heidtman

Something in the V8's favor, in mild to stock form it produces about the same HP and torque of a a radically modified V6..thus avoiding much of the inherent promblems that come with any extensivly modified engine.
e.g. strain on starter due to stiffer valve springs and higher compression ratio.
e.g. they tend to require more attention/maintanance.

...and whatever else I can not seem to recall off the top of my head.

Having looked at zillions of cars, I am really convinced that a proper Rover V8 installation done up in a manner which more or less replicates the factory GTV8 (whether in a roadster or GT shell) commands by far the highest market value. One way to look at it seems to be, keep the drivetrain fully Leyland-esque and the rest as stock as reasonably possible, and the resale value should be good. Rover motor, Rover gearbox, MGC rear end and such. I have seen a number of V6s languish at _really_ low asking prices (no one seems to want them even though I'm sure a fuel-injected V6 GM V6 is about as reliable a power plant as you can get) perhaps because they really seem like "fakes" in a way that a reasonably correct Rover installation doesn't. I don't know whether a carbureted car is more or less valuable than a EFI, but I suspect it just may be given its period appropriateness. I think a V6 even bone stock has plenty of power to make an MG into tons of fun, but it's an odd mix for sure.

Out of curiosity, what have people seen these sell for? There was a _nice_ CB GT conversion down here that sold for $18.8K. That's about as high as I remember hearing.
Bill Withum

you said-
>Something in the V8's favor, in mild to stock form it produces about the same
> HP and torque of a a radically modified V6

I dont want to start an arguement, but fact is that is not true.
A 3.4L V6, the crate motor with all emmissions devices in tact, with a 2 barrel carb, stock intake, air pump and cat converter produces 160 bhp and 200 tq. New, from GM. This is a motor built to go along way, not a high power engine that GM will have to get alot of warentee work from. The fuel injected versions produce anywhere from 160 to 185 bhp stock and 200 to 210 tq stock. after adding a few items and removing a few more, bhp and tq go way up.

What does the 3.5L BOP/R with a 2 barrel (or two one barrels) produce from the factory from stock? What they didnt have emmissions? No fare comparing it to our engine.... ;-)

Maybe your talking about the Ford 5.0L?? Then ok, now we have a sizeable gap.

Now, i'm getting into a which engine is best agruement, but when looking at engines, look at:
Technology placed into it, how they held up in stock form, and of course, people like cubic inches.

I have seen a few V6 and V8 cars that are into the 30 to 40k range for what the owners have placed into them.. When you look at any given car, look at what they have put into it, and even more, what they have not put into it. if you like the color, the styles, power and performance, and can afford the price, then consider that car. There is no true book value on a non-stock car.
BMC Brian McCullough

I am aware of that particular engine and it is (everything considered)nominally built with the focus on the low end to mid.
I do hold alot of credance in GM r&d, and that particular one would be a good choice -for some.
I particularly like the ease of install and fitment..It certainly looks very much at home in the bay.
Of course this is somthing each individual will have to consider/gauge for himself.
I personally prefer the established reliability:performance ratio of the stock configured V8...
137 bhp,193lbs torque (with SU's)

...comparable numbers at a bone stock base.

Jegawatt says, "I personally prefer the established reliability:performance ratio of the stock configured V8...
137 bhp,193lbs torque (with SU's)"

Come on now guys I have motorcycles with more HP than that.

I don't think anyone going through the time trouble and expense would be happy with anything under 200 HP out of a V8, but hey that's just me.
Michael S. Domanowski

YOU ARE SO CORRECT MICHAEL, why bother with a conversion unless you really kick up the hp, much like that pinto engine powered b on ebay a while back. i have to admit that i am a little biased as i had a 215 powered gt and also a v6 powered rdstr and i sold the gt in favor of the 6, and i am currently doing some more mods to my 6 that i am expecting 325hp at the flywheel before the NOS kicks in, but i will know for sure after it is dynoed next month. BILL W, surely to a purist of sorts a true rover car seems to be the highest value but i have seen cars all over the map for resale, i just do not think there is any bench mark for a starting point, afterall you can buy a condition 1 - 2 or completely restored factory car from the uk and have it sitting in your driveway for under $13k, with this in mind why would one want to pay 18k for a non original? it is up to each person to place a value on what they have and the biggest point i believe is as jim b said, it is in the quailty and planning of the work, to see if it practical and works well, i have my b insured for agreed value of 25k and i had no problem with this as i took it to a street rod appraiser that sees the value in conversions. i personaly know a fellow that has a rb b with a 350 chevy, very nice car but he told me he has 50k out of pocket invested in the car, you just cannot ever believe that you will sell these cars for what you invested , just build or buy what you like and drive it like you stole it, jim ps, BILL C, i believe you are talking about bob fishes car? maybe not, but his is a very well done conversion and i have talked with him several times as we started our 6 cars at about the same time, if you are set on an 8 check out chris longos rover 8 with the sebring kit that he has had for sale for quite some time, i have seen 2 of his other cars and he does nice work and i think he is also in your area.
jim m

Bill - another approach to the same answer; if you install a big lazy engine properly you should get 300K miles of road use - perhaps 20+ years. If anything goes wrong you will fix it. The next owner may have to get a garage to find the parts and do the work. Value depends on lifespan as well as drivability so its worth considering kit which will be around for a while.

If you want your money back - plan for a very long life and document your work. When you come to sell it -provide a handbook or spec sheet for every bit of kit you use.

In short -use the MG philosophy - every moving part needs to be mainstream kit.

On the subject of power; be clear what you want - the car will still go round corners at 100 mph - at 120 it needs a very experienced hand at the wheel. 137BHP will get you to 120 - 150 will get you there faster. 200+ is for street racing or track. If its track you want, there are many better, faster, more stable and cheaper cars than an MGB.

some conventional wisdom from the other side..


Michael S. Domanowski stated,
"Come on now guys I have motorcycles with more HP than that"

I was just trying to promote a fair comparison..note I even used the 3.5 V8 numbers, as that V6 = 3.4

Do to the V8 what GM did to the V6 and you will see proportionately higher numbers.

This thread seems to pop up now and then. A little different in text but the same debate goes on. Like Brian Mc, I am also biased toward the GM V6. I was once an advocate of the 215 engine until performance part resources for significant performance upgrades made the conversion a bit pricey for any sizable HP upgrade. It was impossible to get 200 HP without going into the internals of the engine or use air pressure devices or a bottle. If you used either latter HP boost method then you really had a livability problem if the engine wasn't strengthened.

Very simply put a FWD engine used as a RWD engine in the MGB will achieve 200 HP with a header system a cold tube and K&N filter. Brian Heidtmans car has this as an only upgrade. Almost everyone who reads these threads have read my barkings before so it isn't anything new to them. Do not misinterpret what I am saying, I really like some of the V8 transplants. Some of them are totally impressive. Myself and others like reliability, smallness, lightness, longevity, cool running, easy upgrades, yap, yap and so forth, you know the drill.

What I really truly like though is the endearing photo hanging on the office wall of my shop. It is a photo of the plaque on Mike Maloneys car. The father of the V8 MGB endorsed it. The car was the first of the Killer B's. The plaque reads "To Mike and Dann. Well done." Signed, Ken Costello.
Gets me right here.
Dann Wade

I must say I am still very much tempted to go V6.

It also depends on where you are and how easily you can get patrs for it
Here in Australia, everyone goes for the Rover V8, why? they are plentiful, the conversions into B's are well documented and thus the cost relative
As for V6's, firstly we dont get the GM FWD v6 over here, so theres an issue about spares,parts etc (yes we could import it all but $$$$)
secondly, workshops here dont very limited experience with v6's into B's so then the cost is greater because normally they will charge you while they are researching out how to do it.
Lastly for HP, 200bhp out of warmed up 3.5 is not uncommon, I had a reliable 250bhp at the flywheel with a balanced & blueprinted 3.5 with EFI ( federal type)and Block hugger headers
Certainly more than ample for a road going B

Just my 3 cents worth


come on dann, i was there in st louie and saw mike give him that hundred to sign that thing.

just kidding, mike's blue gt is a very nice car and you both have every right to be proud of it, as said before it all comes down to personal preference, i do know this, of all the cars i have and have had my bv6 is the only one that i would never sell and has never left me stranded. i have driven it half way accross the usa and back several times.
jim m

Jegawatt, try it you'll like it! :-)

Steve, you make a very good point. I hope you understand that I wasn't trashing the V8. The V6's here are very plentiful. I sorry you could experience the power these little rascals can produce. But wait! Rover has a good sized 4.0 litre. Sounds good to me!

Jim, I almost jumped out the window when I read that first line! Of course I was in the basement. :-P Mike has gone on to improve the looks of the car. Brian Heidtmans car has the latest 2003 3.4 V6 in it. It is a very nice car. Worth viewing on the site Brian Mc. mentioned

Dann Wade

the problem over here in Oz is we have the Holden Commodore which uses the Buick 90degree V6 of 3.8litres and its a genuine RWD application.
There a lots of these motors around but the problem is no workshop wants to take the time /effort etc of either building a kit for it or even doing one off conversion simply because they dont know how to...
Such a shame as the motor also comes with a factory supercharger in the Commodore range

Still , at least you guys can experience the new Pontiac GTO ... hehehehe


The new GM 60 degree lineups will probably end up over there in OZland as well as Europe. I know they have been approaching these on a more WW scale, so maybe in a few years. If i had a vehicle to drive in this Minnesota winter salted roads, i would drive on down to the GM dealer now.. They have quite an interesting lineup that is coming out.

I would love to see pics of that driveline in the Holden. If it is the same as the RWD Camaros that were built until 2002, then we can expect a few USA guys to have some answers for you in about a year.

BMC Brian McCullough

It sounds like your original question as to relative value is pretty much up to the buyer's purpose for the car. If you're looking for a tire burning, high horsepower road burner then either V8 or V6 would be great if they are modified for maximum performance. If you want smooth acceleration and low rpm highway performance then the V8 would probably be the best solution and the most valuable to you. One caution, if you're not familiar with modern engine management computers and fuel injection, then a carburated engine would probably be best. Very few garages will touch any type of modified vehicle, especially computer controlled ones. On the plus side, fuel injecton and computer control will usually give great performance, good mileage, and should be relatively hassle free.
Bill Young

ou could be right
they are working on a new plant over here to build the new v6 of about 3.2 - 3.8 litres with twincams, multivalves, all alloy ( all the good bits )
but i dont know if its 60 or 90 degree
if its 60
i'll be placing orders to some of you upstate suppliers for v6 conversion bits :)


Steve, isn't that Buick V6 the one that was derived from the 215? About the only difference is that it has two less cylinders and a more widely used bellhousing. It even used the same front cover and motor mounts. That would be an easy swap with more radiator room and as for the headers, worst case you could whack a couple tubes off the RV8 headers I'd think.

Jim Blackwood

GM has a new 3.6L DOHC 60 degree motor, totally new design. Also, the old 2.8/3.1/3.4L design that is also built as a 2.5L for the china market is now coming out as a 3.9L OHV motor with variable cam timing and variable intake runner length. The OHV motor will be used in the conversions, the DOHC may be harder to fit under the bonnet. Sounds like the new 3.6L 60 degree V6. Hmm, maybe i will get to producing that kit? ;-)

BMC Brian McCullough

Jim M, 325 horses at the fly wheel.....WOW. I assume this is your 3.4L V6. I for one am very interested in what you are doing.

Stan Arendts

hello stan. i will know for sure later in march after the dyno runs what it is producing, but from everyone i have talked with at tuning and engine building shops to the folks at haltech that is what i am aiming for. engine is the 3.4 v6 rear wheel version, this is how it will sit, SPFI using haltech ecu, roller rockers, mildly reground cam, balanced and lightened flywheel, forced air induction, lt1 injectors, TB overbored to 55mm, headers with free flow exhaust. so we will see after programming the haltech on the dyno, jim
jim m

Some examples of cars sold.
A customer of ours sold his 74 RD 3.4 4v 178-rear wheel hp 3.4 for $15000 car was perfect. (Black)
68 GT BRG California car with well massage crate 3.4 with 4v carb very fast, Ford 8 inch, Wilwood brakes Classic conversions Front end kit etc. $17500 car went to Japan same person who bought the GT also bought a V8 conversion from Arizona for $12000 with stock rear end stock everything with a stock 215 car was cherry when I saw it at the port ready to be put in a container.

How the parts are matched is important as well how it drives and who is buying.

At the Barret Jackson auction we saw non-original cars go for more than an original car, this could be a trend. How bad do you want it and how much can you afford will determine the prize as a bargain if purchaser is satisfied, yet on someone else’s eyes you pay too much.
Bill Guzman

This thread was discussed between 01/02/2004 and 14/02/2004

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