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Compatibility between FWD and RWD Trans Bolt Patterns

Mad Max

Mad Max

New member
I have a pipe dream of getting an older RWD grand prix from the 78-87 model year and swapping a GTP motor into one with the computer and fuel injection, to make an old school pimp Grand Prix that has modern technology and decent fuel economy. It would certainly be unique and I'm sure I would be the only one at a car show. I would love to paint the car black like my 2005 GTP and have the two side by side for photos. It would really be sweet to find an aerocoupe, but they are damn impossible to find anymore. I could clone one I suppose if I really wanted to.

This would be easier if I could just find a donor GTP to pull the motor and all the wiring I would need. The question is, would the FWD based 3.8 bolt up to a 700-r4 or TH350/400 depending on what trans I wanted to use? I can't imagine the 3.8 being FWD specific and having a different bolt pattern for the trans, I'm sure the block has been the same since it was in the RWD and there have just been differences in the rest of the motor right?

The alternative to that would be to just rebuild the 3.8 in the old grand prix and swap the intake for the S/C. But that leads to the question of compatibility between that old 3.8 and newer FWD ones. Again, I can't imagine the intakes being different dimensions either.

Worst case scenario I would just go with a V8, but I really love the 3.8 and will try to keep it in the car so I have two Grand Prix's of different generations with the same engine, that would be a lot of fun.

Keep in mind, this is hypothetical at the moment, I am just daydreaming of this crap and was curious.
 


nothing between the motors are interchangeable, so you're out on that option.

a swap has been done into those older cars a few times. the most reputable being tranny man dave's cutlass.
 
There is, however, a company that's advertised on LS1Tech.com that makes bellhousings to fit the L36 and T56 together. No, it ain't the TH350/400 or the 700R4, but it's a RWD tranny.
 


yeah, austin was looking at their setup for me for a while. i think they ended up closing the case on it and stopping.
 
That sucks, I was hoping there was still the compatibility. Oh well, as I said this is a hypothetical type of deal, so much would have to be in place for me to even dream of doing a project like that. First is to square away my car before I adopt any more strays lol. Thanks for the info though, I'll continue daydreaming.

Maybe a grand national drivetrain in a GP, that would also be pimp and keep the 3.8!
 
nope i think he had it at the gn set up, find a t-type and destroy it not a beautiful black big body.......lol but if in need of parts shoot me a line family works on gn's all day
 
Jteske88 said:
nope i think he had it at the gn set up, find a t-type and destroy it not a beautiful black big body.......lol but if in need of parts shoot me a line family works on gn's all day
Click to expand...

Thats outstanding, I will definitely take you up on that when the time comes, thanks.

BTW, you popped my cherry, you gave me my first "like". This don't mean we are going steady, I'm not ready for a commitment, lol.
 


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