I have a 85 Z28 that is a factory TPI car. I got a complete drivetrain from a 88 IROC-Z. Now my question is will the wireharness under the dash work with the 88 motor harness ? The 85 has a little box on top of the ecm. The 88 does not. There is a extra pig tail for it. I dont know what it is. So does anyone know if that will effect anything when I plug in the 88 harness ? Any help on this would be great. Thanks.

That's the original MAF module before it was integrated with the ECM.
You'll need the 88' harness unless you can repin the 85'. I'd use the 88', or an aftermarket.

As long as you use the same 85 MAF sensor, you can simply use the original electronics in your car when you install the 88 drivetrain.

However, if you want to use the newer ECM then you'll have to do some rewiring of the 88 harness to mate to your car. There is not short version of explaining this...you'll have to learn and study the factory service manuals. Plan on getting the factory Helm manuals (eBay is the best deal) because http://www.alldatadiy.com is not very thorough back in the 80s.

Mike .
Mr Davis did a nice write up on this swap back in the dark ages

http://www.eecis.udel.edu/~davis/z28/ecm_swap/

I forgot all about his website. Wow, takes me back to the prom burning days.

Thanks for the reply.