There might be another option, the plug that screws into the pump housing Is removable.
Can I just replace this receptacle with an older version that matches the hose end?

When I say plug, there's a sleeve that screws in to the Saginaw housing, then the hose screws into that.

I guess I have a 76 up version that takes a lip with o-ring.
If I could find a 70 version that accepts the inverted flare style?