<VV> Corvair fuel pumps - different designs ?

[Charles Lee]

I only have about 4 pumps in my short experience with them, but I've noticed several different designs and materials of the metal parts.

One thing surprised me was that the center piece (with the valves in it) can be either aluminum, about 2.5 oz., or a heavier cast metal, almost 9 oz !

The grooves in the base plate and the center holes are quite different, too, and I haven't figure if these are from different years or different mfgrs ?

Charlie