So we put in a new fuel pump on the 350 and id start it and run it fine and drive for a good 10miles but when i stop and pop the hood, all the gas is running out of the filter right away and if i try to turn the key 3 mins later, i gotta pump the gas again. When we first put the pump in it held the gas but now it dosent. ideas?

I dont know if this is related to this or not but also after driving and warming the engine up when i turn it off, leave and come back to start it again it starts hard. the starter is cranking and everything and i tried pumping gas and holding throttle down a bit but its not an instant start. and when it does, it wont stay running very easily. when i back out of a parking spot, it will cut off. when i start it again and put in drive, it tries to cut off also. It didnt do this before the new pump. We also re-routed the gas line to the carb from the pump and it touches a heater hose and i heard it might be a problem with gas boiling or something? please help

This is the pump i have. its a 3 line. And if it is the pump, any suggestions for a new one?
Airtex 40777 - Mechanical Fuel Pump | O'Reilly Auto Parts

 

For some reason the gas is running back through the bypass line and to the tank. The pump must not have anything to prevent back-flow. Was your old pump the same bypass style. And yes, the gas siphoning back would also be why you're having a difficult restart issue. I would move the fuel line away from the heater hose, but that's not why gas is running back and leaving you dry.
A simple fix would be to install one of these: Fuel Check Valve

 

alright il try that out in the next few days and tell you how it goes. thanks.

 

Do you have the lines connected to the correct ports on the fuel pump? Double check them.

 

Yes because it's two slightly different size hoses

 

If its a cheap parts store pump the diaphragm may be allowing the siphoning. If it has a slight tear it will pump but not hold pressure. I have super expensive race pumps do it.