I purchased a rebuilt AVS 4426S for my freshly rebuilt 383, installed fired her up was running at VERY high idle @ 4000rpm, shut it down got nasty backfire thru exhaust, did some checking around made sure everything was operating and hooked up correctly. Re started now the engine was screaming I immediately shut it down it once again backfired, but this time it was so volatile that it blew out 2 brand new mufflers. Needless to say I am not putting this carb back on until I can figure out what happened, an ideas would be appreciated. I had a edelbrock carb that i put on and runs perfect, but I would like to keep period correct carb.
