Getting an HEI to work at its best requires full 12 volts which requires looking at the entire power and switch arrangement to assess wheter you can reliably power the HEI from the ignition switch. If the ignition switch receives its battery power via anything less then a 10 guage wire, you are probably making a mistake powering the HEI from the switch. If the switch receives battery power via 10 guage wire, then you have to decide if you can run a 10 guage wire from the switch in the first instance, and whether there are other loads being pulled from that side of the switch. If so, then you will liekly over load the swithc and cause either a failure or melted components.
Using a relay is not perfect, but it does eliminate a lot of issues for the HEI, particularily if the relay is pretty close to the battery or starter and the HEI. The relay is triggered by the ignition switch, and the relay powers the HEI with a full 12 volts, without any voltage drop from long wires, switches. Its not a terrible way to do it with old, older, vintage or even reproduction stock wiring, at least in my view, and I have used a relay to power a HEI on a couple of occasions just for those reasons. It works really well and to me, just a safer way to go about it if your electrical system is less then ideal.
Last edited by Dragsix; 08/26/2022 1:56 PM.
