My buddy has a 650sx with a 750 motor, pump gas compression, porting, 650 ingnition and flywheel, dual taper bore 44's, coffmans pipe, 750 nozzle, 9/17 skat trak impeller, the boat seems to be reving up and not hooking up like it should, anyone have experience with this? Is it the impellor? Also are taperbore carbs more for top end? He's looking for more bottom end for freestyle.