[HTHarry427]

Hi Everybody: I have an Old MSD Timing master 8770 it has the same wiring as the Timing computer BUT it only has a gray wire for the toggle switch. the Timing computer has a black wire and a gray wire to be hooked to the toggle. I have tried working with MSD them selves but the best they could do was " that part number doesn't exist, Are you sure it was made by MSD?". My actual question is do i hook the gray wire to a toggle and then the toggle to ground? Sorry I don't post very often. I just want to use this for starting retard on a locked out ignition system, Race only application. Thanks

[ericnova72]

I may be wrong so you may want to check it out and search some more but...

The older MSD systems as I remember them, for a start retard, you have to put 12v+ to the grey wire while it is cranking to get retard, so the grey wire was commonly hooked to the starter solenoid post that gets 12v+ when the ignition is turned to crank.

[ericnova72]

Go to the MSD site and into the tech forum and search "8770 timing master". I just took a look and there is a thread concerning hook-up of the older Timing Master and how to determine if the grey wire should be hooked to ground or the opposite.