The previous owner converted it to 12V. The stamp on the starter says 6V though.

I have a donor chassis from a 55.1 GMC manual truck for the bell housing, clutch linkages, and a starter. It would be a 6V version though (I assume). Is there a way to rebuild it to 12V? Where do I find the 168 tooth flywheel?

1955.1 GMC.
https://picasaweb.google.com/utasilverado/19551GMCTruck?authkey=Gv1sRgCOPc-ODm5sSK5wE#