HEI Distributor Wiring

[steviemack]

Originally Posted by Steeveedee

What gauge is the wire? The HEI likes as close to battery voltage as you can get it, that's why it's a 12 ga (?) wire. The wire you have may have too much voltage drop when the engine is running. You could check that easily enough, just check with the voltmeter at the connector on the distributor. Is your meter high impedance? It should say on it. I'd recommend a high impedance meter so that not too much power is taken off the wire when you sample it, which could make the voltage reading lower.

I am pretty sure it is 12 gauge wire. It's almost as big around as a pencil. I will double check the voltage when running. Maybe it's my imagination but it seems to be running even better now.

[A1971Blazer]

The wiring on mine was pretty hacked...I got a new engine harness from AAW that was already set up for HEI
Plug and play

[bry593]

Basically, you want to mimic GM 1975 and later wiring. It is 12 AWG, Pink, Cross-Linked Thermoplastic wire (GXL). You only need four feet or so. You will also need an Aptiv (used to be Packard 56) female terminal at the HEI and a male terminal at the firewall junction block.

This is the only 100% proper way to do this (just like GM did it).

The old stainless steel resistance wire should be completely removed from the harness, including the old yellow bypass wire from the starter to the coil. The harness should be re-wrapped in 1.25" wide, non-adhesive, vinyl black tape.

I've done a bunch of 'em.

And, as A1971Blazer says, American Auto Wire is your best source for a replacement engine harness. And it is no problem for them to make it with HEI connectors and wire type. AAW is the best and just an engine harness will not break the bank.