Hi Guys,
Name here is stan.
Just purchassed a 69 camaro with a big block and it has a msd6al ebox and msd distributor and msd coil.
Putting the factory tach back in and orderd the msd 8920 adapter to make it work.
Trying to figure out if it was a voltage triggered or Current triggered from the factory.
It says in the instructions from msd it depends where the tach hooked up originally from the factory to the coil + or - side which I DON'T KNOW.
I guess I could try it both ways but afraid to damage the new tach.
Thanks in advance for any info
Stan

Factory tack hooked to negative side of coil.

Thanks Paul that helps me out a bunch.
This is got to be the coolest site on the web.
Hope I can return the favor one day
Stan

Welcome to Team Camaro Stan!

There are some really nice wiring diagrams in the "electrical basics" sticky at the top of this forum. Here's the link, tach is shown in "dash with gauges" diagram (some of the diagrams will require a password you'll have to get from JimM, but not this one):

http://www.camaros.net/forums/showthread.php?t=93576