A friend of mine put a HEI in his '74 and bought a tack from a '77. He has not been able to figure out what he needs to do to make the tack function. Does anyone have a wiring diagram that he can follow to update his tack?
Thanks,
John

Hi John,

ZWEDE should be able to help you on this one. Try doing a search in the forum on this...

Bob :cheers:

There is a tach terminal on the HEI which goes to a filter (add) on the firewall & then to the tach.

You need the wire from the HEI (w/ filter) on the back of the tach you need switched power, ground, and that signal from the distributor.

The tach terminal on the distributor is not a problem. Jason ran a lead from it into the passenger compartment and then attached it to each of the three leads on the back of the tack. Will it not work without the filter at all? He said he got no movement at any of the three positions. It makes sense to me that he probably needs battery, ground, and then the sense lead all terminated. Is there a schematic drawing somewhere that I can print out for him. Also I would think that the housing itself should be grounded.
Thanks,
John

John

Should work w/o filter & yes there is a power, tach. & gnd. The wiring diagram shows the ground on one side & power above the tach wire on the other side of the connector.

Is the filter something readily available?
John