Here is a picture of the other side of the flywheel. The best I can determine there are 3 sets of numbers: GM 35; 839754 777; and D8 6 (??).
The casting number "839754" with 9 bolt clutch is associated with 1942-53 Chevy All Passenger and 1/2 ton trucks with heavy duty clutch.
D 8 6 = April 8th, 1946 casting date.
The applicable vehicles and casting date would make this a confirmed 6 volt flywheel.
Hope that helps make a sale for you.
