The Stovebolt Site Forums The Shop Area General Truck Talk HEI vs Point. Dist.

I would not repeat that theory too many times. The larger wire does not shield against EMI. The larger wire will help with voltage drop and amp surges. Even though HEI draws pretty low amps most of the time, it does have higher draws.

The plug wires have EMI protection.

The wiring diagrams say 12Ga. Possibly a safety factor included. 10ga is used by many on here.
A 14 gauge will probably work (one size down). But what's the point? Wire the HEI per GM instructions.

American Autowire provides a 12Ga wire. They are the leader in wiring harnesses.

"The average current draw isn't large for HEI. But for a short time, each time the coil begins to charge, they draw a lot of current. It's called "instantaneous current draw" and it's the real reason why GM used such a large wire for HEI systems. Plenty of people have learned by experience that too small a wire diameter can cause problems with the way the truck runs."