1962 Ply with a 318 Poly 4 bbl Edelbrock 1405, headers. The car sat longer than it should have without being ran. Less than half tank of gas. Started it up, idles rough, wants to stall. Drove it a bit and when accelerating it was backfiring and popping through exhaust. It can get up to speed slowly. If I try and get on it it will pop and backfire. Filled the tank up with fresh fuel. Checked carb out and ran a wire through orgunned. Was not varnished inside. Fuel filter not clogged. Floats not stuck. Needle valves not stuck. I didn't check the accelerator pump for a shot. I did not look at check balls. Ran it for 6 miles. Idles better but still pops and backfires on acceleration. I can remove each a/f needle which creates a vacuum and high idle until I screw them back in. 1. Could still be bad gas in the mix 2. Check valves stuck / shooter not shooting / carb still gunked. 3. Longshot but could a stuck mechanical advance cause it? It did this last year and fresh gas fixed it up. I had 50 minutes today to play with it so not a lot of time to troubleshoot. What do you think I need to look at?