The purpose of changing the cam and putting better heads is to make the motor burn more gas which equals more horsepower. If you don't increase the amount of fuel going to the cylinders, how is it going to run better.Re-jet the carb,put the distribitor on a machine and get the timing up to a total 37-40 dgrees. Then get a hotter spark( better Coil). With the Sportsman heads you should be good to .550 lift with Flat-top or dish pistons because they relocate the valve angle which allow the motor the work with more valve lift than the stock heads.
