H1 Oil Pump
Crank to oil pump ratio is somewhere
2.56 turns (revolutions) of the crank to 1 turns (revolutions) of the pump.
Darth here, I have learned that standard #016 and #017 O-Rings will fit the end caps on the H2B/C pumps. #016 on the throttle cam end and the #017 on the line side end.
S/H Series Difference
The S and H series pumps are identical except for cam plate and direction of rotation.