Could someone give me a list of where the grounds should be under the hood of a SD 1990 IROCz with a TPI. I am pretty sure I have them all accounted for but I want to make sure.

The main grounds are the two studs and the rear of the heads (one on each side d/s and p/s) and then there is the battery ground at the front of the block. I belive all the grounds for the ECU are gotten from those locations.

The ones on the rear of the heads attach to the firewall right? Any others?

There are several that go into the wiring harness and probably, like was said above, to the ECM (maybe some other stuff, too). I believe there are 3 or 4 in total they all have ring connectors on the ends to go on those studs.

Yeah the p/s head has a ground wire that goes from the stub and attches to the fire wall. All the ECU grounds go back the the studs on the head. There a few other body grounds for lights and a few in the interior of the car but are not realted to the ECU.

Most of the grounds back there attach to the rear of the heads, but there are others on the firewall and the inner fender. There are grounds everywhere on our cars.