If I swap a 91 TPI engine, harness, ECM, ect into my car, will there be any issue with it working with the dash from my 89?

I don't think the ECM interacts much with the dash, I just wanted to be sure. I know there are some differences with the speedometer, ect.

 

Connection point pinouts are different, so you need to change some things. Your 89 dash will have a cable speedo where all 90-92 engine harnesses were electric. Get an in-line electric VSS for that

Not hard to do, but you need to do some changes

 

yeah, this is where it gets confusing for me. If I'm using a transmission from an 89 and my dash is an 89, then how does the wiring harness and ECU from a 91 matter? Doesn't the speedometer cable go right from the transmission to the speedometer?

 

Pinouts are different most every year. Two big examples are wiper and fan fuse. 90-92 divorced the wiper circuit from the engine harness so using it on an 89 will lose it completely. The fan fuse for 90-92 is at the c100. 89 it's in the c207 on the opposite side of the dash

Your speedo will work fine. The ECM still needs an electric speed input

 

I'm assuming all of this is workable? Will I need one of those $300 speedometer conversions, or can I just get a chop that reprogram the ecm?

I have a feeling you're going to say it needs the speedometer for speed density

 

http://www.jagsthatrun.com/Pages/Spe...eedometer.html

You want number 2

Cheaper versions exist if you look hard enough

 

Well that's better than $300! Thanks for the help

 

You're probably thinking of the cable-x box needed on most LT1/LSx swaps. Completely different

 

yeah, I started off looking at a LT1 t56 swap, so yeah, that's what was in my mind