So I'm definitely a noob here and I understand might be another topic about this but I figured I'd see if this will work.

So I just got a 1986 trans am 5.0fi with no motor and tranny but I also got a 1987 trans am gta with motor and tranny but the body is no good. So I want to put the motor and tranny into the 1986. I was wondering how much work would it actually be. I have the ecm and wiring harness from the gta. But the thing I really need to know is the wiring harness on the driver side firewall by the brake booster will it have to be swapped out as well. Or can the wiring harnesses from the 5.0 work with the 5.7. Thanks to anyone that has some info for me.

 

I am going to bet it will be 98% perfect and 2% getting a few sensors hooked in with some minor wiring changes and you are set.

The main powertrain components, engine and transmission, work together with the ECM and are independent of the rest of the car.

 

Awesome thanks for your input.

 

85-87 harnesses are the same.

 

So even with putting a 5.7 back into a 5.0 it'll all be okay as long as the 5.7 ecm is in it correct. Sorry just trying to make sure I have it all together before jumping into this long project car

 

Dang. Now you've got me thinking about this. I have a 89 convertible with the 305. Now I'm thinking the best way to get my power output up is to replace the longblock and ECM.

This thread has everything you need to know:

https://www.thirdgen.org/forums/tpi/...i-350-tpi.html

 

Should be fine. The TPI setup does not really matter if its sitting on a 305 or 350 block. I know several people who have done this. Just change out the parts listed in the link above.