Sorry Mods..i put it in the wrong forum yesterday

Local car show tomorrow and I decided to put some fuel in my 69 Charger. 440 dual quad exactly what's in my signature. Never had a fuel delivery issue except for those hot summer days where the fuel evaporated. Factory fuel tank Edelbrock 110 GPH mechanical fuel pump. I can prime the bowls on both carburetors using a syringe and some fuel and that usually gets the engine going for 15 20 seconds so the fuel pump can suck fuel from the fuel tank but today we have a tantrum. I left it her up in the air I looked at the fuel sending unit and the hose was cracked so I replaced the hose. Wow under there i got an itchy to remove the fuel sending unit just in case the fuel sock was varnished or covered in crud. It wasn't but I removed it anyways.Drop the car back down prime the carburetors again which are dual 500 edelbrocks on a progressive linkage. Turn her over she goes for 15-20 seconds but I'm not getting any fuel pressure on the gauge. I usually get 6 PSI. So then I start thinking maybe the fuel has varnished in the fuel lines which are original. I take off the rubber hose from the fuel sending unit and also disconnect the hose just before the fuel pump. I put a tube to catch any dirt that would come out and I put compressed air from the rear part of the fuel line near the fuel tank. Air flows freely and nothing came out because the fuel line was dry. Reconnect at the rear check for obstructions in the dual feed lines for the carburetors and those are clear. So then I start looking at the fuel pump. If I plug the outlet with my finger I can put suction on the hose on the inlet and I can feel it pulling on my finger, so there goes the inclination that the diaphragm has burst. So now I'm at a loss I took fuel and poured it down a rubber line which goes on the inlet side of the fuel pump and then shoved that hose into a fuel tank near the passenger front fender just to see if the fuel pump can draw fuel in and it can't. I need a second set of eyes or a second set of ears cuz I'm losing it right now. I can still pour fuel down the access ports near the metering springs on the edelbrocks and she kicks over and runs for 15-20 seconds. Do mechanical fuel pumps need to get primed in order to suction properly does anybody else have any constructive criticism. I have not pulled the mechanical pump off the block but I'm really hoping it's not the cam lobe or The eccentric lever but if it had to be something I hope it's the fuel pump and not the camshaft

A member suggested the fuel pump push rod. I just removed it and from an old post on moparts another user said it should be 3.25"
This is mine below.

I put a vacuum gauge on the fuel tank side and cranked the prior to removal and the gauge didn't move...AT ALL. fuel pump sitting on my bench i put a rubber hose on the carburetor side and I can suck through the tube and move the gauge with my mouth.

How do you check for a flat fuel pump cam lobe?

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?

Sounds like it. Don't bother with gauges, just suck on the tank side port. If you're not getting resistance, the valves are nfg.

Sucking on the carb side should have little resistance.

Since the pump can be reclocked, there's a good chance it's rebuildable, check the Edlebrock website.