HEI conversion question
 

I have a 67 c10 350 3 on the tree and I just rebuilt the engine. while I had everything apart, I wanted to upgrade my points distributor to an HEI. I picked up one from Summit and began reading up on the HEI conversion. Everyone was saying (correctly, I might add) that the HEI distributor needed a full 12v to run correctly and the stock resistor wire wouldn't work because they only had about 7-9v on them. This made sense to me, but when I measured the voltage on the coil wire on my truck KOEO, I had 11.75v with the battery at 12.1 (a little low, I know). With the engine running and the alternator producing 13.5-14.5v, is the any reason to believe the voltage from my stock wire would be less than what an HEI needs to run correctly?
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Re: HEI conversion question
 

I'm not sure what you mean by "the voltage on the coil wire". Are you running a coil with the HEI? If you're talking about the wire to the coil (not from the coil) you can bypass the resistor all together and just run a regular 12 volt wire.

Re: HEI conversion question
 

The yellow 20 Ga. wire that attaches to the coil (+) gets its power from the Orange/White/Purple single-strand wire that comes from the bulkhead connector.
This is the resistor wire. It flows 12 VDC at start up, then current heats it up and resistance increases [and voltage decreases] so the points don't burn up.
You need a separate 12 V feed that does not decrease with running temps.
The HEI coil will fry if it does not get constant 12 volts.
I run a 10 Ga. red wire from the IGN Unfused terminal on the fuse block thru the firewall to the (+)BAT terminal on the HEI coil cap.

Re: HEI conversion question
 

Thanks 68orangesunshine. Heating up and increasing resistance makes perfect sense. I'll run a 10 awg to a 12v switched ignition. Thanks for the replies!
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Re: HEI conversion question
 

Here's a nice little diagram showing the conversion.




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