HEI harness problem - The 1947 - Present Chevrolet & GMC Truck Message Board Network

72 longhorn BB · 10-10-2005, 05:08 PM

Does anyone know why this HEI connector has a 2 into 1 plug?

I got it from a late model donor for my 72 C-20 HEI conversion and I always thought that the HEI needed two separate wires - one for power and one for tach.

I really got this off an HEI, but I think I got the wrong one, or did I?

Can someone help me out?

Thanks

beaterC10 · 10-10-2005, 05:15 PM

Looks like you have the adapter to power the ESC module on the 80's trucks. Since you aren't using the ESC, you can ignore the adapter.

Starscream · 10-10-2005, 05:48 PM

Do you have a tach.

72 longhorn BB · 10-10-2005, 08:32 PM

I'm curious now.........I thought that an HEI would always have the same connector plug, but I guess from what you are saying, the later (80's) versions had this ESC system. What is it?

Also, I currently have no tach, but am planningon getting one.

Why do you ask?

beaterC10 · 10-10-2005, 09:17 PM

ESC is electronic spark control. I had that on both an 83 and 84. They both had the adapter like you have. The tach connection is a separate connection on the cap. I would assume the adapter could be used for anything on the truck that had a spade connector.

86 GMG · 10-11-2005, 10:03 AM

beaterC10 your are correct 83 and 84 i have an 84 that i just had to rebuild the dist. the dist. also has two pig tails or wire harness coming ut of the metal part of the dist. i believe you can cut two wires and jump the to gether and then you can use that dist but without these wire connected to the esc or jumped across it will not fire this is really all i know about these b/c like you i thought all hei's are the same until i messed with mine

you can use the one you have but you will need a buddy that knows what wires to cross for sure and if thats not available than another dist. will be needed best luck and i hope i didnt confuse you due to me not knowing all about these types of dist.

10-10-2005, 05:08 PM	#1
72 longhorn BB Registered User Join Date: Jan 2000 Location: Michigan Posts: 312	HEI harness problem Does anyone know why this HEI connector has a 2 into 1 plug? I got it from a late model donor for my 72 C-20 HEI conversion and I always thought that the HEI needed two separate wires - one for power and one for tach. I really got this off an HEI, but I think I got the wrong one, or did I? Can someone help me out? Thanks __________________ Chuck 1972 C-20 Longhorn 402 BB .030" over (409?), curved HEI, RV cam, quadrajet, dual 3" exhaust, TH 400 ported w/shift kit 1999 K1500 Suburban (old style) 5.7L Vortec 4L60E "No matter where you go, ........ there you are" Last edited by 72 longhorn BB; 10-10-2005 at 05:10 PM. Reason: image tag was wrong

10-10-2005, 08:32 PM	#4
72 longhorn BB Registered User Join Date: Jan 2000 Location: Michigan Posts: 312	What is ESC? I'm curious now.........I thought that an HEI would always have the same connector plug, but I guess from what you are saying, the later (80's) versions had this ESC system. What is it? Also, I currently have no tach, but am planningon getting one. Why do you ask? __________________ Chuck 1972 C-20 Longhorn 402 BB .030" over (409?), curved HEI, RV cam, quadrajet, dual 3" exhaust, TH 400 ported w/shift kit 1999 K1500 Suburban (old style) 5.7L Vortec 4L60E "No matter where you go, ........ there you are"

10-11-2005, 10:03 AM	#6
86 GMG Registered User Join Date: Apr 2005 Location: Tulsa Oklahoma Posts: 943	beaterC10 your are correct 83 and 84 i have an 84 that i just had to rebuild the dist. the dist. also has two pig tails or wire harness coming ut of the metal part of the dist. i believe you can cut two wires and jump the to gether and then you can use that dist but without these wire connected to the esc or jumped across it will not fire this is really all i know about these b/c like you i thought all hei's are the same until i messed with mine you can use the one you have but you will need a buddy that knows what wires to cross for sure and if thats not available than another dist. will be needed best luck and i hope i didnt confuse you due to me not knowing all about these types of dist. __________________ square body trucks an addiction or an investment either way they consume all my extra time and money

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10-10-2005, 05:15 PM	#2
beaterC10 Senior Member Join Date: Jul 2003 Location: Indianapolis, IN Posts: 1,277	Looks like you have the adapter to power the ESC module on the 80's trucks. Since you aren't using the ESC, you can ignore the adapter.

10-10-2005, 05:48 PM	#3
Starscream Registered User Join Date: Apr 2005 Posts: 17	Do you have a tach.

10-10-2005, 09:17 PM	#5
beaterC10 Senior Member Join Date: Jul 2003 Location: Indianapolis, IN Posts: 1,277	ESC is electronic spark control. I had that on both an 83 and 84. They both had the adapter like you have. The tach connection is a separate connection on the cap. I would assume the adapter could be used for anything on the truck that had a spade connector.



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