I see the later Bud wheel and a C head.
Timing cover is also Model B. Timing pin has the elongated boss.
I think I may have one of these blocks. It was imported by Joe Mac that owned Ford Parts Obsolete in the sixties. Do you know of any differences?Yep, most of these GAZ trucks were fitted with B blocks from the mid-1930s onwards although A blocks kept on being made and fitted. The B block trucks are referred to as GAZ-MM.