Hi, i have a 71 SS chevelle that came with the ls5 454. it now has the ls6 with msd distributer and the coil. question is will the original tach in the car work with that setup or not??? and so i dont have to tear the whole dash apart does anyone know what wire i need to find that goes to the signal part of the tach??? thanks for any and all help.

Tach wire is a dark brown wire that goes from the dash gauge connector through a hole in firewall to the negative coil terminal. Tach might work with the MSD (be sure to hook it to the tach terminal on the box), try it and see if it does. If it doesn't work you may have to purchase a tach filter.