New HEI for 460, Gauge Wire for Ign Switch

« **on:** September 30, 2017, 12:01:49 PM »

I'm replacing my mallory mag dist. with a DUI HEI. I'm thinking of replacing my ignition switch wires with all 10 gauge. The red batt wire looks to be at least 10 gauge already but the white and purple look to be thinner. To achieve the 12 volts at the dist I believe running a thicker wire than stock will be needed going from the switch to the distributor.
Can anyone give me an idea of what they're using?

« **Reply #1 on:** September 30, 2017, 12:07:18 PM »

I had to change the original 40 year old wire from the switch to the electrical block. Boat would not fire until I did due to voltage loss but I used the same size wire, fires every time. But you are correct HEI just will not work with less voltage I also run through a relay to keep the volts steady

1977 Challenger

« **Reply #2 on:** September 30, 2017, 12:11:34 PM »

Couple pictures of mine located my relay below the aluminum that the electrical block attached to. You can see the mounting screw for the relay from the top picture

1977 Challenger

« **Reply #3 on:** September 30, 2017, 12:20:21 PM »

Can you explain the relay system?
Is the relay for the HEI?
I have seen the slave solenoids for the starters, the relay your talking about is something else....?

« **Reply #4 on:** September 30, 2017, 12:25:40 PM »

The relay helps maintain and or boost the minimum 12 volts it needs to fire

1977 Challenger

« **Reply #5 on:** September 30, 2017, 12:31:41 PM »

It looks like in your pic that your relay has the ignition wire from the switch, ground, and then the HEI lead?

« **Reply #6 on:** September 30, 2017, 12:33:33 PM »

Also since the demand for voltage is so high with HEI if it's to low it will fry your module the relay helps maintain the needed voltage any cheap relay should work Bosch or any other.

1977 Challenger

« **Reply #7 on:** September 30, 2017, 12:34:54 PM »

That sounds correct it's not in front of me right now and it's been a while since it was done and one to 12v there are 4 wires off the relay

1977 Challenger

« **Reply #8 on:** September 30, 2017, 12:39:31 PM »

Also do not forget to delete your ballast resistor if you are still running one

1977 Challenger

« **Reply #9 on:** September 30, 2017, 12:41:18 PM »

I wish I had a diagram that shows the ign switch, HEI, back of the engine harness, relays and solenoids to add, gauge of wires to use.
I have seen a bunch of stuff on google images, but nothing that is close to what i'm trying to do and make me feel confidant.

« **Reply #10 on:** September 30, 2017, 12:43:15 PM »

I will try to get some better pictures of mine today for you to see when I get home

1977 Challenger

« **Reply #11 on:** September 30, 2017, 12:45:40 PM »

Cool

« **Reply #12 on:** September 30, 2017, 04:19:29 PM »

Ok so here is how my 460 HEI is wired . Wire from ignition switch comes into the electrical block. From the back of the electrical block to the relay (smaller black wire). That leaves 3 wires on the relay. One runs to ground (white wire). One runs to to constant 12 v bat (yellow wire). Last wire runs to the lead on the HEI distributor (blue wire). Then you have your tach wire runs directly to the other lead on the HEI distributor.

1977 Challenger

« **Reply #13 on:** September 30, 2017, 05:24:15 PM »

They say that you only need 1 12v wire and a tach wire. You have what appears to be 4 wires.
How many 12v wires go to the HEI ?
Do you have a ground plugged in to the HEI ?

« **Reply #14 on:** September 30, 2017, 05:36:18 PM »

Just two wires run to my HEI one from the tach and one from the relay supplying the 12 v to the distributor.

1977 Challenger

« **Reply #15 on:** September 30, 2017, 05:43:38 PM »

The relay just ensures you have a constant 12 volts to the distributor. Your going to need to get a constant 12 volts to the relay and then you will use the ignition switch to "turn the relay on" and send the 12 volts to the distributor that's the reason for the 4 wires. Constant hot to power the relay (1) a ground for the relay (2) a wire to "turn the relay on" (3) and one to send it to the distributor (4).

1977 Challenger

« **Reply #16 on:** September 30, 2017, 05:45:40 PM »

I see. Blue is 12v from relay and the red/pink is your tach, the other wires pictured in the distributor photo just go from the cap to the base, and then to the module I assume.

« **Reply #17 on:** September 30, 2017, 05:47:13 PM »

Correct 👍 sorry I am sure I could have explained it different but you got it now.

1977 Challenger

« **Reply #18 on:** September 30, 2017, 05:48:41 PM »

Do you know what gauge is for the colors you used?

« **Reply #19 on:** September 30, 2017, 05:50:18 PM »

I think it's 14...

1977 Challenger

« **Reply #20 on:** September 30, 2017, 05:51:12 PM »

What about a part number for the relay or the size of amp?

« **Reply #21 on:** September 30, 2017, 05:53:44 PM »

It looks like the black is smallest, blue and yellow are a little bigger and then the white kind of looks bigger than all.

« **Reply #22 on:** September 30, 2017, 05:54:22 PM »

Here is the relay

1977 Challenger

« **Reply #23 on:** September 30, 2017, 05:57:54 PM »

The black is smaller it just powers on the relay the others are the same size

1977 Challenger

« **Reply #24 on:** September 30, 2017, 06:09:04 PM »

The bigger wires look to be 10 or 12 gauge.
Thanks for everything. I think I got a good handle of this.
I did read were some put a 30 amp fuse on the batt wire befor the relay.

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