[chief pontiac wizard]

Howdy,
First, I'd like to tell you how great you all have been!
The responses and knowledge is unbelievable.

The tach I've had for over 30 years is wired as follows:
(1) Red wire to RED terminal
(1) Black wire to light
(1) Black wire to under bracket...must be the ground.

So this must be from a TI car??

I plan on using a Pertronix Ign with their Coil.
Is there a way to test compatibility before blowing the tach?

I also have what I believe is a 62 tach wired as follows:
(1) yellow and (1) green to the Insulated terminal
(1) Red and (1) Black connected to the terminal to the left of insulated terminal
(light socket is at a approx. 2:00 location).
It really looks like telephone wire!
I have had this tach for probably 25 years
CPW