I can understand the wiring and relay issues that crop up with the older factory overdrive cars.  The wiring and relay is bad on my ’50 and I simply wired the O.D. solenoid to a simple on/off switch.  The governor wiring was also bad so I had to take it out of the system too.  I do use the overdrive in that car a lot in town driving simply due the car having 4.27 rear gears and working that switch as I come to a stop just becomes part of the driving habit.
 
My ’55 on the other hand does still have the governor hooked up in a series with the solenoid with a toggle switch so it automatically drops out the voltage to the solenoid at low speeds and allows the transmission to freewheel when coming to a stop.  This switch basically stays energized all the time but because the governor is in the circuit, using reverse is unaffected with the switch being ‘ON’.
 
I’ll add that some of the electronic ignition conversions do not take kindly to using the kick down switch under the gas pedal.  By design, that switch when activated momentarily shorts out the ignition so the solenoid can disengage.  That ‘shorting’ design is hard on the converted ignition electronics so I typically recommend not using the kick down switch with electronic ignition conversions.

Lorena, Texas (South of Waco)

I run a Pertronix II in my Merc and using the kickdown is no problem for it. I checked with Pertronix about this before I bought it. So I'll say so far so good. Your mileage may vary with other electronic ignition conversions.

I wonder if the MSD ignition would like the kick down switch?

Durham Missouri

I have an Overdrive in my 32 Ford. It's a Gear Vendors unit behind a 4 speed transmission. I was worried about the problems using reverse, so I ran the power to the OD thru the backup light switch. Anytime reverse is engaged, power is cut to the OD. 
I wonder if that could be done in the above discussed example, where the original wiring is not used?

If the wiring is simply shorting out the coil on the positive side, then I don’t foresee any major problems with the MSD distributors and the kick down switch.  The only issue I’ve seen with an MSD ‘ready to run’ distributor is where the voltage supply had been resisted down rather than running the full twelve volts which caused an early failure of the module.  I would suggest talking to the MSD reps and asking about the potential for damage as a result of momentarily shorting out the system and if voltage surges or spikes are an issue with this.  I can speak from experience that the Mallory Unilite distributors do not like the kick down switches as those units did not like the abrupt changes in voltage that resulted from shorting out the ignition.


That sounds like a good alternative to using a governor.  I’m assuming a relay is being used in conjunction with the backup light switch?

Lorena, Texas (South of Waco)