The intake sucks , the carb is probably a little too big.
The heads could be a problem too 'if at the very least 'the valve job isn't good.
You could blame the heads or you can blame the cam...'The head does not flow as cast or without porting Beyond .490 to .500.'...
But I blame the guy who put it together and picked those parts more so LOL no offense. You should go with something around .500 to.520 and 300's duration with [email protected] w/ 106-108 lsa.