Backfiring out carb and wont run right

Another question for the experts.

Fresh rebuild on a 360 with a refurbished Edelbrock 1407 750cfm carb from national carburetors.

With a cold start, the engine will start rather quickly and then sputter out. Restart and pump gas pedal to keep it running and it will spit fuel out the top of the carb and sometimes spits fire. After a couple more restarts, the engine is warm and I can get it to idle. When driving, if I give it just a little of gas, the motor will hesitate and act like it wants to die, if I give little quick shorts bursts, it responds well. I haven't really driven the car because I am still putting it all together.

I have checked the timing which seems to be good. I changed fuel pumps but I am getting the same issue. I am constantly adjusting the carb trying to fix it but the issue persists.

I just cleaned out my fuel tank and installed a clear fuel filter just before the pump. When running, the filter will fill up to just below half. Am I just not getting enough fuel? But I had this same issue while running with 3 feet of new fuel line to a gas can.

Any help is appreciated.

Thanks