I am right in the middle of a TPI + '727 retrofit for a 38 streetrod.
The harness that came with the TPI unit was the wrong one so I decided to make one from a FWD V6 harness and some other spare harnesses.
I have followed the diagrams from the autozone website and chevy thunder. I have found a discrepancy in the diagrams. The two diagrams show the EST bypass and EST reference wires pin number and color in the opposite pin pisitions.
I am using a small diameter distributor from a 91 TBI, a corvette 727 and a heavily modified FWD V6 harness, on an early TPI manifold.

If anybody knows FOR SURE which are the right ECM pins for the ignition that would be awesome. and whoever has the wrong diagram needs to fix it.

 

okay. after some time away from the solderiing iron I have looked at two other diagrams and they all are the same on the EST stuff except for the chevy thunder diagram. I think I'll ditch the info from chevy thunder.