As I remember, the earlier pumps will bolt on, but there is a water hole that has to be plugged and the 8BA block doesn't have the oil passages the earlier pumps needed. It's probably better to just go with the later truck pumps. The Mercury or truck bellhousing (and starter plate) I mentioned above is your transmission adapter. If you don't have one, I have either truck (cast iron) or Mercury (stamped steel) and the associated starter plates available.