Voltage at cranking - less than 12V

[stallion112]

I've been running an MSD 6A box for over 20 years with a Ford magnetic pick up distributor. The distributor was worn out so I decided on a Ford distributor with points (to keep the small cap due to limited room between the motor and expansion tank, and to keep the cost down) but use the Pertronix Ignitor to replace the points.

The motor will only run for a few seconds (rough) and then stall out. I've played with the timing but it sounds close enough to at least start and continue running.

Long story short, I've verified the wiring is correct, the Pertronix pick up is working, and the MSD box is working.

The only discrepancy I can find is that I do get 12.84 volts with key on, but it drops down to 9.3 volts when cranking. Pertronix and MSD both require a full 12 volts while cranking. The "ignition on" wire is wired directly from the battery so no ballast resistor is involved.

I'm assuming the voltage drop is due to the Tilton high torque starter. The car doesn't have any accessories, no heater, defroster, etc.

Is there a trick to wiring to maintain a full 12 volts while cranking?