Technical Flathead fuel pump help please.

Hi, I’m finishing up the flathead swap in my 29 roadster and just installed a new offenhauser mechanical pump using the stock gravity feed tank as supply and 1/4” hard lines. I’m getting no fuel to the bowl but if I loosen the supply line it’ll flow but leak at the fitting. Is there a trick to the fuel lines? I’ve also tried a stock soft line and have the same issue. Thanks for any help!

 

Maybe pics will help. It also flows just fine with lines tight but bowl removed

 

Here it is

 

Are you using the correct length fuel pump push rod that will work with your manifold?
Flathead fuel pump push rods are not all the same length.

Here's a good start re: this topic.
fuel pump push rod - The Ford Barn

 

Seems it’s not even getting into the bowl let alone into the pump mechanism. There must be a blockage. In order for the fuel to flow in, air has to be allowed to escape. Are there shipping caps installed?

 

Sorry to waste time guys but seems fixed now. I added a few gallons of gas and I think that increase of supply pressure overcame the vacuum. Thanks for the help and hopefully first crank up in a bit

 

Is the gas cap vented? Try removing the gas cap.

 

Sometimes with a new fuel pump that may have sat on a shelf for a long time, the valves stick and need some pressure to unstick them.