Managed to bag a super rare motometer tacho for my 58 ragtop resto.

However, being a 30-40 year old gauge not suprisingly it came with no instructions! I dont wanna wire this wrong as I'm NOT gonna find another one, thus I was wondering if anybody know how to wire this in to the car?

The car its going in is a 58 bug, but running 12 volts electric with a full MSD iginition system. Pictures below shows the gauge, and connections.
At a guess I'd think the switched live goes to terminal '12', it needs to be earthed to the '-' treminal, and the tach output wire needs connecting to the 'z' terminal. However, as its a older gauge do i need a MSD tach adaptor?
Cheers in advance for any advice.

Dude



