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MG MGB GT V8 Factory Originals Technical - Will a GM 4.3 work?

I have the opportunity for a free GM 4.3 from a S-10, along with a T5 from an unknown source. My 78 RB doesn't need a new engine, but the thought of a bigger engine with a 5 speed is interesting. My first question, will the 4.3 fit, or will it require modifications (big hammer, cutting torch, etc.) to the body. Second question, is this a decent engine swap in general, or should I wait for something else (it seems the 3.8 is very popular). Thanks for the advise.
Ace Brandt

I believe the 4.3L is a 90 degree V6, while the 3.8L is a 60 degree V6. It is simply a 350 V8 casting with two cylinders cut off, so you will find it too wide for the chassis (without making major modifications.) That is why the 3.8L is a better choice. You will also find that the bolt pattern for the transmission is different on those two particular engines.
Jeff Schlemmer

Jeff & Ace,
The 3.8L is a 90 Deg as is the 4.3. The 3.4L is a 60 deg. As the car in question is a 1978 the 90 deg would be the same work as a Rover V8, meaning nothing. The block should fit but you are on your own for mounts and Cross member. If you can fabricate you own stuff then the 3.8L is an option, if not look at the 3.4L or Rover as kits are availible for these.
Regards,
Mike

Mike

Will a GM 4.3 work? Yes. Is it the best engine for a transplant into an mgb? Probably not. The BOP V8, 302 Ford, and 60* V6's are probably better suited for the mgb and have more after market support and parts available. I've owned both the BOP and 60* conversion cars and they are great conversions. Having said that, (ready for the caveat?) the 4.3L and 3.8L engines will work admirably in the mgb. I have had both engines in my sebring gt. If you can live with an mgc (a fine motor car in it's own right), you can live with the 90* gm v6, and have 50-100% more power. Unless you are going with an RV8 style header through the side engine wall, the headers will be a major obstacle, as there is minimum of clearance at the side rail area and headers for this application have to be hand fabricated. I would do a lot of research on this subject before I decided on what engine to put into my mgb. Here are a few pics of my red 3.8/4.3 gt.

http://community.webshots.com/myphotos?action=viewAllPhotos&albumID=546617929&security=FMumab
Mike Maloney

I just wrote on another spot about:
"I can get a Free X.XL VX with other parts with it- is it worth it?"

http://www.mgbexperience.com/phorum/read.php?40,319984

The answer is that you will end up spending as much money anyways. The motor is only a small portion of the total components. Read the postings...

As for the T5, I would presume that it is a S10 T5 and worthless in so many ways for the conversion, however, small enough to pack and sell on ebay (if your into that) and not a bad item to pick up just in case it is a Camaro or Mustang T5 which can be used- then you have saved money. Find out how many inches back from the front of the gearbox (back of the bellhousing) to the centre of the shifter and quite a number of us can give you a generic answer of what its from, otherwise get the serial numbers off it and look it up on a T5 website.

-BMC.
BMC Brian McCullough

This thread was discussed between 25/01/2006 and 26/01/2006

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