I am swapping in my 87 TPI motor into an 85 Trans AM that had the 85 TPI system on it. I am doing a full motor swap and was wondering whats different about the wiring harness, computer and any problems I will have. Also guages are different, if I swap in the 87 computer will I have to swap guages? The tach in my 87 Formula redlines at 5 and shifts at 4800 the 85 T/A redlines at 6... whats the difference in TPI systems? Thanks for any info guys!

 

You might get better answers on the TPI forum.

 

Okay so you are putting an 87 TPI motor into an 85, right? Your gauges will still work the way they did before. Your shift points are not determined by the ECM. Are you changing to the 87 computer and harness or just the ECM? If ECM only there are some things that will have to be changed but I recommend the 87 ECM. Do a search for 165 swap. The two TPI unit are the same as far I know. I'm not sure if the '87 had a cold start injector.

 

the speedometer in my 87 car has a 140 speedo and the 85 has an 85 speedo. and yes computer will be swapped in with motor. should i swap guages to keep 140 or what?

 

The speedometer is cable controlled from the speedo gears in the tailshaft of the transmission. As long as you are using the same transmission then there's no problem.

 

im using mine because i just rebuilt it so ive got problem can guages be swapped?

 

The 87 has an electric speedo, so you'll need the dash harness too. As far as the cold start injector, the 87 has it too. The other difference is the 87 has 1 piece rear main seal and center bolt heads. I wen't a step further with mine and put the 88 & up serpentine belt on, I hate tensioning belts. I doubt that you'll have many problems with the swap, especially since it sounds like you have the 87 complete to swap the parts over from.

 

Sorry, I thought he was putting the motor from the '87 into his '85. The speedo for the '85 is cable driven.

 

He is, I was just pointing out the differences between the two cars.