79 450 SLC WON'T RUN
 

I need help!! 79 450 SLC, I replaced the fuel pump and filter, pulled tank and cleaned and reinstalled. The car started right up and idled fine for about 10 minutes. I shut it off and aoput 10 minutes later tried to start it and it would not start untill I poured a little gas in the air intake. When it started it would not idle (like it was starved or overfueling because I could hold down the accelerator and after several backfires it started to run at high RPM with the gas pedal down. It will not idle now and just dies. Also it will start back up only if pour in a little gas and does the same thing all over. ADVICE PLEASE.