HI I installed new msd iginiton on 69 charger. Fried new tac . Any suggestions on why? Thx Thomas

 

What is the tach referencing? Did you connect it to the tach output on the MSD or is it still hooked to the coil?

 

HI It is hooked to the msd tac output! Thx

 

Could be new tac was junk, it happens.

 

So you're using the gray output wire on the msd, good. You mentioned the tach being new, have you double checked the wiring diagram? Have you checked the vehicle wiring? Sometimes wiring gets pretty screwed up over 40+ years of owners making shade tree "repairs"