I have two chevy 235 oil pumps apart thought it would be fun to post side-by side pictures:
The one shown on bottom and left in attached photos is a '55-57 model with longer pickup tube matching oil pans of that time.
On top & left is a post-1958 pump; it's internal gear cavities have different profile than the older pump. Also there's a small lip machined into bottom of cavity, around the perimeter of the driven gear underneath where the teeth mesh... It's definitely not wear, since it's circumference is a little outside the driven gear. Maybe it's just sloppy machining?
