I am just completing a v6 to v8 swap in my 1991 firebird and i have encounterd the problem of not having a tach that works. i am using an MSD ignition and i have herd that you can wire the tach into the ignition somehow but im not sure which wire to use. anyone ever done this before??

 

You've connected the factory tach wire to the tach terminal on the box and it still doesn't work?

 

weve been trying to locate the factory tach. we first thought it was the white wire that was connected to the coil originally, but when we tried to connect it it didnt work.

 

That's exactly how I did it on my 91 using an MSD Digital 6 box....

 

which color cable did you use and where was it located??

 

I used the white wire going into the coil, the one that normally has the grey barrel connector on it.