Thanks for the pictures. That's a nice 'ol Jimmy. Looks to be somwhere between a 520, & 640 series. Once they got into the 700 series, 10 stud wheels were more common. Look at the base of the distributor, where it mounts to the engine block, & see if you can locate some numbers there. The ci. displacement is usually the first three numbers stamped, at this location. The previous numbers you gave are the engine casting numbers. I don't have a way to decifer them.
