Here's how I wired up the Pertonix unit in a '48 M5 truck with Champ 6 engine and OD. I got the diagram from Pertronix. You need to add a 7 or 8 ohm heavy-duty resistor so that you don't short the battery to direct ground through the Pertronix unit when the OD kickdown switch is activated. The resistor had a ceramic body about 1/2" square and 3" long. I bent up a bracket from aluminum sheet about 2" wide to wrap around the square body and mounted it to the firewall.

I asked Pertronix the same question when I put an Ignitor unit in my 1948 M5. I got a 6 volt, positive ground unit from Bill Cathcart for the Champ 6 engine. Pertronix sent me a wiring diagram they worked out for the Packards with overdrive.

Depending on the vintage of your overdrive and the type of relay and solenoid you have, the exact wiring may differ. On my old-style T86-1D transmission, there is only the solenoid switch, no governor, no lockout switch. Pertronix shows adding a 7 ohm, 5 watt resistor to the circuit to limit the current draw through the Ignitor when the hot side of the coil is momentarily shorted. I found an 8 ohm, 20 watt wire-wound resistor in a ceramic package at Radio Shack for $2.29. I took a 1" wide strip of thin sheet metal, bent it around three sides of the resistor and left two tabs sticking out so that I could screw it to the firewall. It works great. It ought to be about the same for the 12 volt, negative ground unit, but you can always email Pertronix on their web site or call them.

Gary Ash
Dartmouth, MA
'48 M5
'65 Wagonaire Commander
'63 Wagonaire Standard
www.studegarage.com