Just finished my new engine install and a new ChevyDuty wire harness. Can't figure out how to wire up the HEI distributor. ChevyDuty techs can't help with any advise at all. The wiring diagrams supplied with the harness don't give you an HEI option. Anyone out there had this problem? How did you solve it? Any help would be appreciated. Want to get Baby Blue back on the road. Dr. Mike
I put an HEI in my '57 GMC V8 years ago. Easy to do and works well. Assuming it is an early HEI (pre-computer with only two connections) one connection is tach output and the other is +12V. Looking down from the top the tach connection is clockwise from the +12V connection. The 12V feed needs to be fairly hefty. I ran mine through 10 gauge wire. You have to eliminate the "ballast resistor" from the circuit. The easiest way to do it (and the way I did mine) is to find a connection on the back side of the ignition switch that has 12V when the key is in the "start" AND in the "run" position. Make up a 12 gauge wire with an in-line 20 amp fuse. Connect that wire from the ignition switch directly to the BAT position on the HEI. You do not have to connect anything to the TACH position, but if you want a tach, most semi-modern tachs (like my Sun Super Tach III) work just fine when connected to the TACH output. Ive attached a page that I found somewhere about troubleshooting HEIs. Note that the picture of the cap is from the INSIDE so the TACH and BAT connectors are reversed. One more tip. An HEI is a reliable source of good spark, however when it dies, it dies in a hurry, not slowly like points-based ignition. I now (after a $65 tow charge in the middle of the night) keep a spare module (less that $20), a 1/4" nut driver and a flat blade screwdriver under the seat. Attachments: https://talk.classicparts.com/images/attachments/4352f3a606dc494a.jpg
I put an HEI distributor in my "57 350/350 several years ago and have been very pleased with the results. Stepside57 in the Central San Joaquin Valley of California
