1966 thru 1983 Pre - Alpha
Pre - Alpha Upper Housing
A. Top cover
has a hump with a hole thru it. Alpha is flat.
This housing will fit an Alpha lower housing but will not fit a Gen II lower.
Pre - Alpha Lower Housing
drive shaft has a preload pin on the top of it. Alpha does not.
The 2 5/16 Diameter below the water pump is smooth. Alpha has threads in it.