Factory tach

I'm putting the dash together on my 67 barrcuda and I have the tach in the cluster but it was not wired, so can't find a wiring diagram in my factory service manual , was wondering if anyone has any idea how to wire this thing??

Thanks Mike

One wire goes to coil negative. Can't remember where the 2nd one goes.
I can post more info after work in the morning.
Dunno if you had a new board installed but you should before installing.
Also not picking but that is a 68-9 tach. 67 needle sweep is from about 8 oclock to 4 oclock.
Also chl part # on back, there were factory 6 cyl tachs.
More info later....oh go to mymopar.com and download the factory service manual. It will have wiring there

looks like a 1970 tach
one wire for power to fuse block and one wire through grommet in firewall to go to coil(-)

Typical fuse box has a unused slot at 1 end. The fuse clip for hot at switch on is there but the clip for line out is missing. The factory tach wiring included that fuse clip to insert there. If you dont have that factory wiring, a inline fuse holder stashed behind the column door works. Other end of this wire goes on the longer of the 2 contact studs on the tach.
Signal wire from coil goes on the shorter of the 2 studs.
More important is the chassis ground. The tach is grounded to the inst' panel via the 3 mounting screws. Then the entire inst' panel relies on another hardware link where it mounted into the dash with screws.
Add a real ground wire. Attach it with a ring terminal at the lower center of the 3 tach mounting screws and route it to the chassis behind the left kick panel. Sheet metal screw, ring terminal, and toothed washer required. Basically, copy what factory used at ALT gauge connections everywhere you can. A male/female spade terminal disconnect about 4 inches below the tach ( also stashed behind column door ) will come in handy too.
Also be aware that the circuit boards inside these OEM tachs don't live very long, especially when attached to aftermarket / high energy ignition systems. Aftermarket offers a newer more compatible circuit board too.

Thanks for the reply, will have to wire it up and try it to see if it works, does anyone know where I could find one if these circuit boards

Here you go 67-74 Tach Board with Calibrator Built In - rte

That will work !!! thank you