I have asked quite a few people and they have said that you cant put a 5 speed behind an L98 on my 88 Trans Am GTA. Anybody have any experience with this? I know it can work because they put that setup in the Corvette, is it body fitment issues? Any minor fab that can be done to allow this? I have an 85 z28 that i pulled the motor for a pickup and would like to put the Borg Warner 5 speed that is in it to use?

 

Very commonly done & is a direct swap. Just need to swap the pedal assembly over too & address a little rewiring.

 

Thanks, most have told me its a big job, what are the wiring issues between the 5speed and 700r4 besides clutch safety switch?

 

The reason they say you can't put the T5 behind the L98 is cause of the factory power rating. The T5 wasn't used behind the 350 because GM thought it had too much torque.

 

My 85 Z28 TPI is converted to a L98/ T-5. I found a 85 Vette 4+3 manual trans ECM with a stage II performance chip for the L98 engine.


Yours being a 88, a custom burned ECM chip may be the answer for the L98/T-5. 86 on up is a better, faster and more programable ECM than a 85 ECM like mine.

 

The T5 was never offered in the C4. There was the 4+3 til 88 then in 89 the ZF6 came out which is very strong. (Heavy and expensive to have rebuilt might add too)

T5 will hold up to an L98 unless you get really stupid with it.

 

Who said the T-5 was ever offered in a C4? My car originally had a 305 TPI with a 700R4. When the L98 and the T-5 was installed, I had to find a ECM for a 350 with a manual trans. An 85 is a Basta*d ECM and the only one for a 350 with a manual trans was a 85 C-4. If I used a 85 C-4 with a auto trans I would have idle issues. If I used the stock ECM with the 305/auto trans, the L98 would run lean and idle high. This was an easy upgrade using my stock wiring harness. I don't have a idle issue. (1300 rpm cold and 750 rpm hot). This car runs great!