RWD to FWD years/bellhousing pattern

Do the rear drive BOP V6 engines, (1980's) have the same bellhousing pattern as the transverse engines in FWD cars? I need a replacement engine, (1981 Buick 231 V6) for my Jeep. I don't know when GM changed to FWD and stopped making RWD cars and if they changed the bellhousing pattern.
Thanks, Patrick

 

Some of the GM FWD motors, don't have motor mount pads on the sides of the block.
Double check.

 

the 90 degree Buick V6 engines in RWD vehicles used the normal BOP bellhousing. The 60 degree V6 engines in RWD vehicles had the smaller bellhousing as used in FWD cars....same as the 90 degree Buick V6 engines used in FWD cars.

So you need a RWD 231, not a FWD.

 

So is there a year break point for what I need? The engine that is no good was an 1981, but I have an 1984 Olds engine and it looks the same as the Buick. Just wondering what years donor car I should be looking for.
Thanks
Patrick

 

Any Buick V6 that's designated a 3800 instead of 231 will have the FWD pattern. Here's a good resource for GM bellhousing patterns.
http://en.wikipedia.org/wiki/List_of_GM_bellhousing_patterns

Bob

 

Buick, Olds, Pontiac and Cadillac V8s and the Buick RWD V6 share a common pattern. The last Buick RWD V6 was '87 or '88. I think any after that would be be a FWD application and have a FWD pattern. Look for something out of a '78-'87 GM A or G body. Some had Chevy V6, but many had Buick.

Bob

 

If the engine looks the same (especially at the back) then it will probably work.

RWD 84 oldsmobiles wer available with the 231 or the 252 (which looks like the 231)