engine date/voltage

hello to all of you out there in interweb land. i have an st70 engine serial no. st70-154078.
my questions are...
1. when does this lump date to?
2. is it a 6volt or 12 volt model? it has a hitatchi flywheel and the points are behind the flywheel.
3. if it is a 12volt model, can i use the stator plate and flywheel to upgrade my 6volt c90e motor that currently sits in my frame?
4. if so...what else would i need? 12volt coil, 12volt cdi? new bulbs and anything else that i cant think of right now!
looking forward to your replies.
oops. nearly forgot, i have a boiled battery so i am asuming that my reg/rec is frazzled. i connected another battery to the bike and genny is putting out 10.3 volts on a six volt model. what should the output be on the 6volt c90 when working correctly?
thanks again everybody.

1. around 1970
2. 6v. Always 6v if you have points.
3. nope. This flywheel doesn't even fit the c90, as the Hitachi needs the S-tap instead of the L-tap.
4. in case you fit a suiteable 12v ignition: cdi, regulator, bulbs, battery. You can re-use the 6v coil.
5. voltage depends on revs and battery load. When the voltage on the battery is 5v instead of 6v, the charging current should be 7v.

Thanks for the info. I think i will stick with my mighty six volts and invest instead in a hot cam and uprated valve springs.......for the time being!