Okay, Here is the problem I brought a 86 Trans Am from a one family ownership. In which older brother sold car to younger brother in college. Younger brother Blow up engine and transmission. Parents had car fixed by dealer who farmed out car to third party to replace blown engine with new crate engine after transmission rebuilt.

When I brought the car, I found out wrong base engine was installed. The crate engine was a LG4 type and not a LB9 type that was installed in car from the factory. Dealer said that the problem was the new crate engine was wrong and that I had to replace it. Now this is where the question comes in.

My Trans Am is a mid year production run with the 1987 drivetrain in it. I have a replacement engine that I got that is a 1991 TPI engine from a IROC. The engine only has 40 thousand miles on it. I know the difference between them. Would it be quicker to change the harness and the prom chip to match my new engine or change the new engine over to the older type.

My new engine has the extra goodies on it like headers and mild cam. I'm also having my transmission rebuilt with a stall convertor and corvette internor parts.

The Trans Am is a 1986 WS6 Bird. It has LB9 engine, 4 speed Overdrive Transmission, Posi Rear, 4 Wheel Disc Brakes, Crossed Laced 16 Wheels.

 

Welcome aboard, I myself think it would be easier to just swap motors and keep the current MAF harness/computer in the car. If the cam is mild you should be okay with your stock chip from the 86. Just be sure to use the intake base from the 86 with the cold start injector.

 

Thank you for you insight on my problem. I have known about the cold start injector in the left runner and the cold start solenoid in the TPI base. I have talk with someother people about this. What I have planned was to install the cold start solenoid in the new water pump housing and switch the left runner and TPI plenums assemblies with the new and older engine in the car.

I was also thinking about the painless wiring harness to replace my harness in my car which has a few wires that are too short in length at the junction block in the firewall. Plus when the orginal owners changed the engine some of the plug ends have bare wires which I sealed up with RTV.

About the cam it has not been installed into the block yet. I thinking about a cam in the range 260/272 or 272/284 which would give me that little cam loping.