Aftermarket Tach install ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

smorg007 · 01-03-2011, 11:18 PM

I finally gave up and purchased an aftermarket tach conversion upgrade for my 72. It installed in the cluster gauge without cause or concern and looks great. I have two questions;
(1) Next step refers refers to using the existing 3/4" hole in the firewall or if you don't have this hole "DRILL IT". Problem is it does not say where this hole should be drilled to match factory placement.
(2) The supplied wiring diagram shows connecting the brown wire to the negative side of the coil with the supplied eye connector. I have an HEI distributor so I don't have this type of coil. My HEI distributor has a male spade connector on the cap for tach, so I assume I can cut the off the supplied eye connector and replace it with a female spade connector and connect as though I was connecting to the neg. side as coil?

If someone can post a picture of where this hole is in the firewall I would appreciate it and let me know how to connect to HEI so I don't damage my hard spent investment.

Thanks in advance.

skokie · 01-03-2011, 11:32 PM

If I remember correctly this " so I assume I can cut the off the supplied eye connector and replace it with a female spade connector and connect as though I was connecting to the neg. side as coil?" is what I did to my 68. Since I dont have the truck here I cant go out and look.

smorg007 · 01-04-2011, 11:28 AM

TTT
Still looking for a picture of firewall where hole should be. Please!!!Help

treveiger · 02-18-2011, 02:04 AM

interested also, free bump

smorg007 · 02-18-2011, 12:06 PM

Quote:

Originally Posted by treveiger

interested also, free bump

Hi treveiger

Another board member answered this question with pics on one of my other threads. Here's the link http://67-72chevytrucks.com/vboard/s...d.php?t=439292

treveiger · 02-18-2011, 12:17 PM

Thanks!!! Did you get your tach working with your HEI?

smorg007 · 02-18-2011, 12:21 PM

Quote:

Originally Posted by treveiger

Thanks!!! Did you get your tach working with your HEI?

I'm still working on getting it replaced so right now I don't have a second tach that I've installed. I've looked at several suppliers and some actually say that their tachs work with HEI and some say their's won't. I assume you bought a tach conversion kit. Where did you get yours?

treveiger · 02-18-2011, 03:42 PM

No im actually looking for a tach from summitracing and want to make sure i get one thatll work. Im thinking about this but not sure it itll work...

http://www.summitracing.com/parts/SUM-G2907/

1quik70 · 02-18-2011, 08:59 PM

I put a Cyberdyne tach in my last cluster. I cut the housing down to actually fit inside the gauge cluster itself. The led sweep matched the factory markings on the glass. It was a really sweet install, I wish I had some pics. When the key was off it was a run of the mill dash, hit the key and the tach came to life. I plan on doing it again, so I'll take pics!
Posted via Mobile Device

01-03-2011, 11:18 PM	#1
smorg007 Registered User Join Date: May 2010 Location: Redding, Ca Posts: 371	Aftermarket Tach install ? I finally gave up and purchased an aftermarket tach conversion upgrade for my 72. It installed in the cluster gauge without cause or concern and looks great. I have two questions; (1) Next step refers refers to using the existing 3/4" hole in the firewall or if you don't have this hole *"DRILL IT"*. Problem is it does not say where this hole should be drilled to match factory placement. (2) The supplied wiring diagram shows connecting the brown wire to the negative side of the coil with the supplied eye connector. I have an HEI distributor so I don't have this type of coil. My HEI distributor has a male spade connector on the cap for tach, so I assume I can cut the off the supplied eye connector and replace it with a female spade connector and connect as though I was connecting to the neg. side as coil? If someone can post a picture of where this hole is in the firewall I would appreciate it and let me know how to connect to HEI so I don't damage my hard spent investment. Thanks in advance.

01-03-2011, 11:32 PM	#2
skokie Registered User Join Date: Oct 2003 Location: San Jose Ca. Posts: 3,354	Re: Aftermarket Tach install ? If I remember correctly this " so I assume I can cut the off the supplied eye connector and replace it with a female spade connector and connect as though I was connecting to the neg. side as coil?" is what I did to my 68. Since I dont have the truck here I cant go out and look. __________________ RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234

01-04-2011, 11:28 AM	#3
smorg007 Registered User Join Date: May 2010 Location: Redding, Ca Posts: 371	Re: Aftermarket Tach install ? TTT Still looking for a picture of firewall where hole should be. Please!!!Help Last edited by smorg007; 01-04-2011 at 11:28 AM.

02-18-2011, 02:04 AM	#4
treveiger Senior Member Join Date: Jul 2010 Location: South Dakota Posts: 4,093	Re: Aftermarket Tach install ? interested also, free bump __________________ 1969 Chevy c20(Miss Hackjob)

02-18-2011, 12:17 PM	#6
treveiger Senior Member Join Date: Jul 2010 Location: South Dakota Posts: 4,093	Re: Aftermarket Tach install ? Thanks!!! Did you get your tach working with your HEI? __________________ 1969 Chevy c20(Miss Hackjob)

02-18-2011, 03:42 PM	#8
treveiger Senior Member Join Date: Jul 2010 Location: South Dakota Posts: 4,093	Re: Aftermarket Tach install ? No im actually looking for a tach from summitracing and want to make sure i get one thatll work. Im thinking about this but not sure it itll work... http://www.summitracing.com/parts/SUM-G2907/ __________________ 1969 Chevy c20(Miss Hackjob)

02-18-2011, 08:59 PM	#9
1quik70 Registered User Join Date: Apr 2010 Location: Jeffersonville, Indiana Posts: 136	Re: Aftermarket Tach install ? I put a Cyberdyne tach in my last cluster. I cut the housing down to actually fit inside the gauge cluster itself. The led sweep matched the factory markings on the glass. It was a really sweet install, I wish I had some pics. When the key was off it was a run of the mill dash, hit the key and the tach came to life. I plan on doing it again, so I'll take pics! Posted via Mobile Device



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