I have an '88 iroc I just got not long ago, but I also have a '90 engine with cut harness and '89 ecm and prom. I was just wondering if swapping in these things would provide much improvement and what other modifications would be necessary.

 

Unless the '90 engine has a lot lower miles than your current engine I don't see much of a point. The only real difference between the 2 is that the 88 is a MAF system and the 90 is a MAP system. From what I understand MAP is harder to adapt to mods. Because of that difference you need a '90 PROM, anything older will not be compatible. I'm no expert though, so hopefully more will chime in. You may have trouble dropping the 89 PROM in the 87 because of VATS.

 

The 90 engine can work just fine being controlled by an 88-89 ECM, so long as you swap the necessary parts over. In this case, that would be the mass airflow sensor, and removal of the MAP sensor.

Since neither the 89 nor 90 use the 9th cold start injector, the ECM & PROM should have no problems with the 90 motor as long as you use the 89 MAF.

 

If your 88 doesn't have vats that might present a problem, you may need a custom chip with the vats deleted, or you could use the chip from the 88.

other than that the motor should run fine with the 89 maf setup.