Thought I'd share some of my work here. So far with the ignition and coil being powered by a relay (which is in turn triggered by the old Coil+ brown wire), it's running great. For wiring the relay I used the directions in the article here: http://www.hoigto.com/tech/powerHEI.htm only with a couple changes. First of all, I used 12AWG wire instead of 14AWG, since it had to come off the battery, go back across the firewall, then forward all the way to the coil. Second, I used a 15A fuse right near the battery since I hate using fusible link wires. I'd much rather use circuit breakers or fuses any day. I'm using a 30A Tyco relay that I got a couple of at a local car audio shop. My only complaint is that I wish I could've gotten a relay connector that's permanently mounted in place so that if the relay does go bad, I could easily pull it and swap it, without having to unmount anything.

Here you can see my HEI module and relay installed, and part of the ground loop. The ground loop connects at various ground points along the body (including the wiper motor) and then directly to the battery's negative terminal.


Bad engine ground? What'chutalkin'bout? Just to guarantee a good engine ground, I connected the cylinder head directly to the battery's negative terminal as well via 1AWG welding cable with heavy duty lugs soldered in place.


Since there was a ground wire at the PS pump mount, I added a new one there as well. I think that with the huge head/engine ground, this one might be a bit redundant and unnecessary though. What's your take, Dan?


Low voltage to the starter? Surely you jest, madam! 2AWG for the positive lead, 4AWG for the ground. Both welding cable again


Wiring mess around the battery terminals not necessarily cleaned up, but organized at least.


Military spec battery terminals. Everything bolts in place. I love it.


There are still alot of wires with connectors just crimped into place. Those were used just to get something in place quick, and will be replaced with high quality, soldered-on terminals and insulated with heatshrink tubing, like the distributor wires connected to my HEI box. I just need to go get some more solder and tubing

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Those battery terminals are really impressive - I never saw anything like them before.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

I got them from www.wranglernw.com. No affiliation, but they're the only place I've seen that has them commercially. I think they get them in bulk from government surplus.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Those are US Military battery post terminals. They can be had from NAPA in the Belden wire/cable line. Positive: 728223. Negative: 728222

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Yeah those are pretty much the same thing.

Hey Dan you think that with the big honkin' cylinder head ground cable, I could lose the one connected to the PS mount, or you think I should keep one there?

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

You could lose the P/S mounted ground cable if you'd like.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Kinda what I was thinking. Glad to know we're on the same page.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

Err…that what you're calling the ground isn't a ground at all. It is in fact the starter solenoid feed wire, and it will never carry anywhere near enough current to require more than a 14ga wire (stock is 16ga and is plenty).

The starter grounds via its mounting.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

No kiddin, huh? Same with the mini starters? Using a smaller solenoid feed wire would definitely make it a little easier to make them into an actual starter harness for the sake of neatening things up.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me

No foolin', same for the mini-starter.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

sorry i havent been around much lately, i see on the linked site that it provides more power to the hei module, i would also assume that would put less stress on the underdash wiring system, which at least in mine, is already not the best at 40 years old...is that the general idea? more power and less stress on the oem system? any other benefits i missed? looks good!

That's another benefit, yes. The primary reason being to avoid shortening the operational life of the HEI module. Not exactly a pretty installation, but it works. I'm currently piecing together parts to make it a much cleaner and factory-looking installation now that I'm back in the States a couple months ahead of schedule.

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'74 Duster w/ HEI ignition, beat to snot suspension, A904, 8.25" 3.55 SG rear, still being tuned up and gets 17 MPG

Know how they always build a better idiot? That's me