Tach question

[Green Monster]

76 K5, putting the gauge cluster back together. Tach never worked right, always read way too high, like 5000 when it was probably only 2500 to 3000. Distributor is HEI, but the back of the tach has a three-prong plug labeled "coil, 12v and ground." Did these come stock with points and a coil? If so, do I need a new tach that will work with HEI? I think the PO Jerry-rigged it with two plugs, one hooked to ground and the other to coil or 12v.

 

[6872xtc]

HEI vs points doesn't make a difference except for the "correct " terminals. But it sounds like you either have a wacky tach, or a 6 cylinder one. I have no idea how you would figure out what is up.

 

[sweetk30]

this guy makes fixes them . http://tachman.com/

and there was a thread a few weeks ago on brand new units and they have updated rpm range over the stock if i recall.

 

[imiceman44]

this guy makes fixes them . http://tachman.com/

and there was a thread a few weeks ago on brand new units and they have updated rpm range over the stock if i recall.

At those prices, it's only worth it if you are restoring.
You can get new tachs for less.

 

[Green Monster]

Thanks everyone for your insight. I looked up the harness at LMC and it doesn't look like the harness I have. 76 has factory HEI. So I think the PO Jerry rigged it. Will order the new one and hook it up.