i have a 1987 camaro iroc z28 350 tpi and i'm wiring in a MSD street fighter ignition box(same wiring as 6al msd box) this box has a gray wire to go to the tach, which wire is my tach wire on the back of my gauge cluster? originally the tach used the white wire comming from the ignition coil and that is re routed to the box i need to kow which wire comming from the back of my cluster i need to splice it into. thanks!

 

GIJason91 - Hey did you figure out were the Gray "Tach Wire" from the MSD box goes?

 

You only use one tacho hookup ;
the tacho wire to the box you are currently using or the tacho wire to the grey ; not both

http://static.summitracing.com/globa...5_frm29772.pdf