Gm style HEI

[Red Cricket]

Im installing a GM style HEI in my 65 coronet. I need a hot wire from some where? Where is the best place to bring the wire from? What to do with the existing coil wires? Im not looking for a "factory" look just reliabllity and smmoth preformance. Tks

 

[493 Mike]

Im installing a GM style HEI in my 65 coronet. I need a hot wire from some where? Where is the best place to bring the wire from? What to do with the existing coil wires? Im not looking for a "factory" look just reliabllity and smmoth preformance. Tks

A key switched hot wire?
Mike

 

[Dodge33]

Im installing a GM style HEI in my 65 coronet. I need a hot wire from some where? Where is the best place to bring the wire from? What to do with the existing coil wires? Im not looking for a "factory" look just reliabllity and smmoth preformance. Tks

I did this same style of deal on a 50 Mercury, and I am thinking that we put the new
wire onto the starter side of the solenoid, DO NOT put it on the battery side, cause it
will hot all of the time. Now that I think it out better, you need to use your + side of the
coil wire, to be hot at the HEI. You will need to get into your original harness, and go
to the base end of coil wire, where it connects to, and you may be able to just go to
the bulkhead... but make sure you use a 12 gauge wire to the HEI. I was thinking
a custom project at first so just read through this, and you should be able to figure
it out. Good Luck!

 

[Red Cricket]

Thanks All. My wiring was a mess. No coil and wires with no ends. Alt wires missing ends. Will you continue to use the resistor? Some say put a wire in back and hide it...??? Some go to the switch...I like Simple and reliable. So a good choice would be use the positive side of old coil? Just cap off other wire to old coil? Would Posistive coil wire be big enough? The more ya read the more a guy can over think!! TKS

 

[493 Mike]

Thanks All. My wiring was a mess. No coil and wires with no ends. Alt wires missing ends. Will you continue to use the resistor? Some say put a wire in back and hide it...??? Some go to the switch...I like Simple and reliable. So a good choice would be use the positive side of old coil? Just cap off other wire to old coil? Would Posistive coil wire be big enough? The more ya read the more a guy can over think!! TKS

I used the 12 volt side of the ballast resistor to activate a relay to feed battery hot to my HEI. I hid that and a new open frame coil required for the HEI under a aluminum cover (rear of right inner fender). I took 12 volt battery positive from the starter relay stud.
Mike

 

[Carcinogen]

I also had to use relay for battery power, had too much voltage loss using old stock wiring. Would start and rev, but under load it would backfire through carb. Also using separate button for the starter.

 

[Geoff 2]

[1] If using the factory coil, the bal res should be kept in circuit.
[2] The only way I can see of using the GM module [ a good upgrade ] with a ballast res coil is using a relay. The method in post #5 is a good way of doing it.

 

[70rcode]

Hi RED C,.....I'm considering to try the GM HEI on my Plymouth also....As mentioned, getting full battery voltage Delivered to the Hei is Important & a Start/Run Relay battery feed avoids excessive wiring harness Resistance & pesty voltage drop & ign performance issues..... As most GM Hei wiring schematics show No Ballast resistance is being used with the 0.7 ohm Hei coil, & most of our Mopar equivalent External coils are in same 0.7 ohm Resistance range, just emulate the Oem GM wiring without Any ballast resistor....Only if running an exotic < 0.5 ohm ign coil would need a 0.5 ballast.....

 

[71charger_fan]

I bought the distributor and coil from these guys' Ebay store. I just put the start and run ignition wires on the same coil terminal and it works great.

https://crtperformance.com/

 

[70rcode]

Nice looking, affordable ign system.....How does that low resistance coil work ?

 

[71charger_fan]

I like the set up. Went with a one-wire alternator and was able to get the voltage regulator, ignition box, and ballast resistor off of the firewall.

 

[Geoff 2]

Sorry,
Info in post #8 is incorrect. Mopar ext coils are 1.5-2.0 ohm, not 0.7 ohm.
And you do NOT run a 0.5 ohm bal res with a coil that is < 0.5 ohm; not unless you want to compromise the performance of the HEI system.

HEI wiring diagrams show no bal res because HEI used low resistance E core coils.