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MG MGB GT V8 Factory Originals Technical - Not an MG question...

Hello, all!

I recently purchased an 1977 Alfa Romeo Spider, and I'm looking to replace the stock engine.

Since the Alfa forums I've been to seem to be full of purists, who consider such an idea to be blasphemy, I thought I'd post here where the thought of stuffing a V8 (or 6) into a tiny classic car is more welcome.

My question is, what would be the best engine to use for something like this?

I want to bring this car up to date, and do away with the carbs in favor of fuel injection, and I don't want to attempt to put something in there so large that it turns the thing into a sled.

I reside in Indiana, so I'm sure there are tons of shops that can put a 350 or 351 into damned near anything, but I'm curious if there are other options.

Cost is somewhat of an issue as well, and while I do expect to shell out some cash for such a project, I'm not looking to starve, or live in the car.

If anyone has any warnings, tips, or stories to tell me about your experiences, please do.

I'm new to this, and anything would help.


Caleb Harber

Having had an Alfa Romeo 164 Cloverleaf I would be tempted to follow a middle road an use the wonderful 3 litre V6 with its beautiful chrome inlet manifolds.

I don't know about its US spec but in the UK 24v cloverleaf version produced 240bhp.

Like many of these ideas the limiting factor may be compatable gearbox bell housings.
David Witham

Well I have my Bias as everyone does. SInce you are in the US I thonk your options are pretty open, it all comes down to the space in the car and your goals.

I am a Ford guy, in a MG the Ford 302 (not 351) fits quite well. IT is a hair smaller than a Buick motor wich is what caught my eye wne I began my conversion. The 351 with it's taller deck hieght mandate hood work. 302/5.0 parts are a dime a dozen as they are in Ford trucks, cars, SUV's since the 60's. I was just at a Wrecking yard and saw no less than 5 complete 5.0's, mostly in Big sedans. The mustang crowd has been very active and has large aftermarket support.

Measure up your car, and search the net, I bet someone else has doen what you want to do and will be a great source of info...
Larry Embrey

For a conversion with a minimum of re-engineering there are three dimensions that you should check. The diameter of the bellhousing, the height of the engine from the bottom of the sump to the top, and the length from the bellhousing face to the front pully. One of the smallest engines being used in a lot of MG swaps is the GM 60 degree V6. There is a lot of good information on this engine at Bill Guzman's web site.
This engine comes attached to a good 5 speed manual trans in several applications and was even a fairly good fit in my MG midget which is much smaller than your Alfa.
Bill Young

Go with David & michel's suggestion. Looks great!
Carl Floyd

Hey, thanks for all of the input, folks.

I'm still doing research, but what are your thoughts on a 13B rotary conversion?

Caleb Harber

the rotary has a high crank centerline so you might run into trans tunnel issues,one engine you might consider is the 2.3 turbo coupe engine from a tbird.i have one in a 74 mgb it is fast and fun to drive,very good engine lots of parts and tech surport for the engine.
ja adams

Caleb, you might want to take a look at these web sites for ideas and experience. MG Engine Conversions
and V8s in Little British Cars
Lots of different conversions to look at.
Bill Young

I put a Mazda rotary 12A in an MGA very few mods neccesary none in engine compartment,sits on stock mounts. Only welded in changes were rear trans mount and widened the tunnel to clear the turned around backwards starter. see pic here
R J Brown

There are one or two MGB's going around with rotaries in them. They do however seem to come up for sale fairly often.

A big favourite of mine is The LEXUS V8, a kind of "dream motor". Not too expensive Big faviourite amounst the Kit car brigade. You'll often see articles about people using them. Lightweight, huge amounts of power, vastly more when tuned up a bit. Overhead cams, spring loaded split gears on them, rotating cam followers. Very long life. The starter motor is tucked away on top in the valley of the V and not obtructivly on the side. very low plenum. Double electronic 'distributors', one per head. I would have used it instead of the Rover 3.9 except of the registration problems that causes in Australia (The Rover motor is legit because it was a factory car, the RV8 & GTV8).
On the other hand with the Rover being crammed into so many MGB's over the years alot of problems already have off the shelf solutions.

Copied this out of the archive. Guy called Stewart (Stuart?).
Lexus LS400 V8
The engine dimensions of the Lexus V8 is 700 mm (28") in length, width and height so it is a neat cube and should fit inside the 'B engine bay with out needing to modify the bonnet (hood>
Size: 700x700x700mm (28"x28"x28")
Weight: 462 or 470lbs
All alumunium
Code: 1UZ-FE
The later versions had VVTI (1997+ I think)
4.0l capacity
32 valve, quad cam
Most come attached to an auto box
190kw at 5100rpm (no VVTI)
206kw at 6000rpm (VVTI) peak torque (402Nm)
10.0:1 compression (no VVTI)
10.5:1 compression (VVTI)
Respond well to turbos/superchargers
Cost: AUD$800 bare to AUD$2500 for complete half cut

Other versions include:
4.7l 2UZ-FE with an iron block 173kw
4.3l 3UZ-FE is the newer version of the 1UZ-FE and is aluminium 206kw - 5600 rpm. Peak torque is 430Nm at just 3400 rpm

They make a supercharged version over here and made a car called the Bullet Roadster based on an MX-5 (Miata). I hear there are some dragsters around the world with this engine producing good power - over 1000hp.
It's also been used in a triumph.

Caleb - apologies if this thread appears to have been hijacked back to an MG discussion (what did you expect!!) I am building an MGB using the Lexus motor as described above, yes it's a very neat motor and will fit in the B engine bay with firewall mods but no bonnet mods (I think I can even get away with a sprintex in the valley.)
One of the major bonuses with this motor is that it was made with 3 different sump locations - front, mid and rear, so fitting around a crossmember is a little less of a hassle. Not sure how it would go in your Alfa, or what the availability/ price of such motors is in the US.
Good luck with your project - your car should be whatever you want it to be.


PLEASE! Document your conversion and submit an article, with pictures, to the V8 newsletter.

I'm sure there will be a great deal of interest in this conversion.
Dan Masters

This thread was discussed between 06/09/2005 and 14/09/2005

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