I think it depends on the pertronix unit your using, some of those have the rev limiter and cdi already in them, then theres no need for the msd, did you use the one that replaces the points only?? in that case you can use the msd, you will have to do some searching for the wiring though, in my 74 duster I have an accel dizzy, and a Mallory 6al, used both the brown and blue wires from the ignition switch, not sure what colors your wires would be, you have 2 wires that go to the dizzy from the msd unit, with the pertronix how many wires come off of that??