440 tuning troubles

sounds more like an intake valve leaking and popping back thru the carb under accelleration,or lean condition on primary side.you will need to do a leak down test on the cylinders to verify this.a compression test wouldn't hurt.but sounds like a problem with an intake valve.or possibly a bad plug wire.if it is a valve problem it could be a sunk valve from not having hardened seats and running unleaded fuel or homeboy valvejob or mr port nicked a seat when performing the porting work.this is just my opinion.....I'm sure their are some hemi guy's out there to chop me off at the knees for offering up my opinion but the way I see it an engine is an engine...besides a slanty is practically a hemi!!! :cheers: