Marine Distributor on Car Engine

I don't know why you'd want to use that. I cannot for the life of me remember if those actually rotate backwards or not...........depends on the cam / intermediate gear teeth. If it has centrifugal advance it may or may not "go the right direction."

The way to tell.........

Attempt to "spring" the rotor CCW while holding the shaft. A B/RB rotates CCW so the advance mechanism will allow you to move the rotor CCW "against the spring." If it is locked it may not matter

There MAY be an advantage to this if it's useable: Might reduce high RPM spark scatter due to looseness/ shift in the intermediate gear, etc