Willys 1950 1/2 Truck Bell Housing Swap

Guys: I am building up a 1950 1/2 Willys truck that came with the F134 engine but is in poor condition. I'm adding a the twin stick PTO to run the belt pulley off the back and the winch off the front. I have all the parts now to do this, with my most recent find being a good running F134 motor. The good motor is from a 1964 CJ5 and of course is running a 12 volt system. I know I need to swap out the bell housing from the CJ5 to match the clutch linkage for the 1950 1/2 truck. The bell housing that came with the CJ was the expected 804308 with the clutch linkage hole in the rear of the unit, a closed end 12 volt starter with 9 tooth drive gear, and the fly wheel has 129 teeth. I also have the correct bell housing for the truck with the F134 engine being a 802929 which as far as I can see all the mount holes match and the starter mount holes are spaced the same with the same size mount bolts. I know if I used this configuration I will need to step down the voltage to the original 6 volt gauges that came with the 1950 1/2 truck. I have a step down regulator that should work. I assume I only need to connect a 12 volt wire from the ignition switch to the step down regulator and then to the voltage regulator on the back of the gauge cluster. Also, I will need to change out the water temp and oil pressure sending units, I think the amp gauge and the fuel gauge are fine? Does this sound right?

My real question is if I want to return this vehicle to a 6 volt system, I have a correct open end 6 volt starter, with 9 tooth drive gear, and the correct 6 volt generator and voltage regulator, but I will need at least a different bell housing because the starter mount holes are different then the 802929 and I believe the fly wheel was 124 tooth for the early F134 engines with the open end starter. So what bell housing do I need, and do I also need a different fly wheel and rear engine plate? Thanks for the help.