Just completely rebuilt the top end of my 350 abc. 286 comp cam blueprint aluminum 195cc heads 64cc combustion chambers. Edelbrock Victor jr intake. Stock HEI distributor. Holley street warrior 600cfm carb electric choke. Everything was fine for about 2 weeks and out of nowhere today I’m driving down the road at part throttle I’d say around 2000-2500rpm and it backfires through the exhaust and kind of hesitates. If I mash on the gas it seems to disappear. It isles fine no noticeable backfire or misfire. Everything minus the carb is new on the top end. I double checked the accelerator pump adjustment it seemed fine at .015” initially I had thought it was because 3 plugs backed out a bit on bank 2 but I snugged them back up and still the problem persists. It was dark when I was trying to diagnose everything so I couldn’t see if the plugs were fouled at all but it doesn’t seem consistent to me that that would be my problem per se. some ideas would be appreciated. Please spare me the criticism as I’m still in school for automotive tech and haven’t quite covered everything yet but have been using this project as a learning experience.