Hi guys, im new to this and i hope i'm posting this in the right place. about a week ago i got my 1957 f600 with a 272 back from my friend who did the rust repair for me. well this truck ran great since i bought it, and the previous owner had the engine rebuilt. and when i brought it back home it sat for about 3 days when i fired it up it ran long enough to go from the shop to the house (about 500 ft) and then just started, id call it chugging its like its running just fast enough to turn over. it smooths out for about 10 seconds with the choke on about 90% then starts "chugging" again and when you move the throttle it will just die no matter how slow you go to try to get it to climb. turning the distributor does not make it smooth out either. it still has the factory holley 2bbl i think its a 500 cfm. it has a new fuel pump if i can remember it was around 6 pounds i cant remember for sure. since this happened i've replaced condenser, points gapped to the spec in my shop manual, new coil, new wires/plugs, cleaned the carb with a fresh rebuild kit, tried a couple different metering blocks i have around that i know are good. the float level was set to just under the sight screw. new fuel lines and filter fresh gas. double checked the valve lash. also replaced the carb base gasket and intake manifold gasket as well. replaced the wiring from switch to coil and resistor with new. its the mechanical distributor. the only vacuum line is the brake booster and i closed it off because i already know it leaks vacuum. im stumped i have absolutely no idea what to do now. i figured something wouldve changed when i did all this and nothing changed i don't know where to go from here i'm hoping someone can help? i can include a video of it running if that helps. because no matter what i exchange on carb the symptom is the same, turning the idle mixture screws doesn't change anything either. im at a loss im so frustrated with this thing its never given me any problems in the past 3 years and it just happened all of a sudden i have no idea what to do. im 19 and still learning so im stopping before i screw up something even worse. any help is appreciated, thanks!!