so i get my hand on 305 tpi, im running a tbi. so i wanna swap to a tpi setup. ok so i pull this engine out of a 87 iroc, and i know there is two kinds of tpi maf and sd only thing is i dont know whats the diffrence. also i had the harness off the tpi so i thought it was going to be easy but one prob i thought well ill just run it like an 87 but when i looked for the plug for the speedometer. i found out it was diffrent. so what my real question is... if i can get a wiring harness for a 90tpi can i use it on the 87 engine and if i can what do i have to do to my car do i have to add any sensors. i wanna try to run it like a 90 set up is that possible? thank for any imput.

 

I could be wrong here, but I think you will have to find a harness from at least an '89 or a '90.

You would also need a new computer with the '90 harness because it is speed density

The '87 harness is different, you could use it but you would have to splice in what ever is missing from the original harness.