ok i recently picked up a 305 TPI went throught it and its amazing and i only paided 125 it came with a cut up harness so i went out got another harness (the orginal has the seprate burn off mod so i got another the same) uncut just the engine side to the computer now my question would be is how to power the tpi harness i know there is a 12v hot and possibly a 5v reference the other thing is i would like to use the orginal steering colume thats in the 1980 and not have to switch that to a 85 colume but by doing so would that cause problems? most everything else i have figured out but powering the ecu.

 

Only need to supply 12V and switched 12V to the ECM as well as the feed to coil from stock key.
No need to touch column
Coil (Ign ) feed is also switched power to ECM
Need 85 TPI ECM wiring diagram for correct power hook ups

 

ok i did find a wiring digram and i see that the ecu gets 12v power already from the battery so that should be covered as for the coil power i could just run excesting to the tpi disturber would i be on the right track for this? also here is the wiring digram from chevythunder.com

 

From the Factory, the TPI ECM gets power though a connector under the dash, close to the ECM. It's C207(IIRC). The power comes to that connector from the fuse panel. You 80 fuse panel will have fuse protected Batt+ and Ignition power sources that you can use for this. Your 80 also uses very close to the same dist, I even think the BATT connectors at the dist cap are the same.