Factory Tach Hook-Up

[Dynaride]

Trying to figure out how to hook up the factory tach and if it will work with my set up. 71 swb w/454 stock HEI dist on engine has a spot for the tach hook up. Only see a red and a black wire coming out of the tach, should there be three and how does it hook up? Research leads me to think red to switched 12 v black to ground and should be a green wire for tach input??? Any help is appreciated!
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[jons70]

Originally Posted by Dynaride

Trying to figure out how to hook up the factory tach and if it will work with my set up. 71 swb w/454 stock HEI dist on engine has a spot for the tach hook up. Only see a red and a black wire coming out of the tach, should there be three and how does it hook up? Research leads me to think red to switched 12 v black to ground and should be a green wire for tach input??? Any help is appreciated!
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The instrument cluster itself is grounded so the housing on the tach is grounded already. The red wire is the switched 12V or as its indicated on the back of the tach and the black wire is the signal wire from the distributor. Not sure if the factory tach will work with the HEI, but I hope it does because I have the same setup as you. Haven't tried it yet, still finishing off the interior

[leddzepp]

Factory tach will work with hei, never had a problem.
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[jons70]

Originally Posted by leddzepp

Factory tach will work with hei, never had a problem.
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Excellent! That's just what I wanted to hear after going through all the trouble to find a tach cluster and restoring it.

[farmall]

Good to know. I will be doing the same but my gauge face needs a face lift first.

[Dynaride]

Thanks for the replies! Cluster looks awesome jons70!
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[jons70]

Originally Posted by Dynaride

for the replies! Cluster looks awesome jons70!
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Thanks, good luck with yours. Its a nice touch to have the factory tach in there, rather then one strapped to the column
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[Lattimer]

I just put one in my truck 2 weeks ago. Red wire to ignition hot, black to tach connection on the HEI. I did put a tach filter in line with mine jus tin case as I had read of some having a bouncy needle.

[NC_John]

Originally Posted by leddzepp

Factory tach will work with hei, never had a problem.
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really? I read somewhere it wouldn't. That's great- my 70 was already switched to an HEI distributor and I didn't want to mount an external tach.