Maybe some one took the good pump off and put a bad one on. I have had access to about 40 BB motors in various stages and that have been sitting for years and decades. Some late 70 motor have those pumps on them, and late 60 motor with the newer late 70 style pumps. What ever a person got from the parts counter.

I am basing what I believe from data in the service manuals, and the part numbers for impeller that where listed in the parts manuals. I appreciate the pictures and info.