Gary,

<< R-640788 and 108AA19-ALBSP-3VT.>>

That part number is very interesting.  The "SP" suffix does not show up in Oildyne's product codes.  I would assume it means "special".  The 'LB' indicates a reversible pump with a back pressure circuit.  Since they added the SP, I would not expect it to conform to there current schematics for their LB pumps.  You and others with similar vintage pumps may see different operational behavior.  In particular, I am thinking of Bob Belshe's ability to push the gear up with the spool valve in the down position.

The part number for the pump currently on my test stand is:  108AM19-CLB-3VT 

Chris

 

 

Chris Zavatson

N91CZ

360std.