If I'm reading this right, your suction test indicates the check valves in the pump are stuck open. To clarify, you should be able to suck through in the direction of fuel flow but not the other way.
My guess is the pump dried out and gummed up.
Unlikely to be a pushrod or cam problem that develops while sitting. Those would have been showing up before the car was parked.
This is a rebuildable pump yes?
It's the Edelbrock serviceable? No idea..i know you can clock the housing and plane the ports where you need them.
I can suck from the fuel tank side and draw 5psi of vacuum from the carb side. Reversing the suction from the carburetor side i can draw 7psi from the fuel tank side.
Does that mean the check valve is blown out?
