Looks like you might be missing a wire or 2. Anyway you can find/locate a wiring diagram? Most tachs I think r black-ground,red-bat/hot,yellow-light,green-coil/ign. Some old tachs may have an extra wire (white I think) for 6 volt. Looks like on yours white with black is ground,orange is light,short red wire would be power and yellow to coil/ign. Like I said,best to see if you can find a diagram on the web,I'm just guessing. My old Sun tach is hooked up to tach lead on my hei in my 57 and my new moon tach is hooked up direct to my ECM on the Canso. If yours is made for a 6 cyl and not changeable to 8cyl the RPM will be out.
-- Edited by hawkeye5766 on Saturday 10th of December 2016 06:44:41 PM
The white wire says pick-up
The yellow says tach power
The orange is power for the light
The chrome body is the ground
I just wonder if it's 6 volt???
Or if it's for a 6 cylinders??
Can it be used on hei???
Was it meant for a points ignition??
Hard to tell from your pic,looked like black going to white. What is the stubby red wire with mar connector hooked to?? If you have a tach lead on your hei should work fine....but not a 100%. Like I said my old tach works fine on hei.
