426 motor reving on its own and no power after half throtol

the motor ran fine and then i put a power now valve on it and a boysen excelerator pump cover on the carb.

now if i give it throtol over half throtol it just bogs right down. low end is still pritty good but when i shift some times it bogs a little for a sec.

also some times when im coming into a turn and pull the clutch in it will start to rev on its own then it will stop after a couple seconds. soooo....... What up? :|

should i put a bigger main jet in it?