I have both the intake and the exhaust cams in mine.With the Holeshot headers and high mount can,K&N pods,advancer,stage II jetting. I'm not sure what my hp is, but it does run good. As far as gas milage,when your sucking more air,burning more fuel,you can go faster to the next station. I need gas every 100 miles. I just picked up some new throttle cables,when I put them on,I'll try and bump my holeshot needles down a 1/2 notch and see if I can squeeze a few more mpg.