[Gaz64]

John,

I still fail to see how fitting an exhaust valve of 00 (no bleed) causes your concern. The inlet ball is OPEN at rest, which will not allow pressure buildup within the pump chamber.

Similar to early Holley float bowls. They had a hanging steel inlet ball which seated by pump pressure. It had a .011-.013 open clearance.
The late Holley bowls have a viton rubber inlet valve AND a .010 vapor bleed back to the bowl. Without the bleed (or blocked), the pump can discharge as the engine heatsoaks.