after sitting for 5 hours my car went from running great to running terrible

its a bone stock 79 318 with a 2bbl carb

i just dont know what happened. the past few days ive been messing with this thing getting it ready to drive around town. i flushed the tank, replaced the fuel pump(the old one leaked) and replaced the filter, topped it off with gas, and it ran perfect. i started it and let it run for at least an hour. i drove it around my field and it did great and shifted fine. this morning i replaced a leaky freeze plug and topped it off with 50/50 antifreeze. i fired it up this morning and it ran like a top. i leave the house in my other rig for 5 hours and come back expecting to cruize around in my new toy and it runs terrible. i drove it up and down the street and it backfires and hesitates. i checked the plugs, wires, cap, rotor, changed the spark controll box(had an extra one lying around). then i tried pulling plug wires one at a time. if i pull the #6 plug wire it goes from almost dying at idle to idling fine. if i pull ALL THE PLUG WIRES on the passenger side, it STILL IDLES FINE. im so confused. can a carb just die in 5 hours? do i have a bad head or bad headgasket?

:prayer: PLEASE HELP ME MOPAR MASTERS :prayer: