[jonzcustomshop]

I have no idea what size the motor is, I was just guessing ...
this one has the tiny rad, and an oil bath air cleaner, the 63 has the same rad, a 2(!?) blade fan, and a paper element aircleaner.
the dipstick on the 2 motors are a little different, the 63 goed straight down in in the center on the side of the block, and the 64 is a little to the rear and at a little bit of an angle...