Unless you are an Expert or Pro rider, I would really concentrate on suspension and handling before major motor work. Pipe, silencer, light porting, and VForce reeds should be all you would ever need, head work might require race gas, big $$$!. I'm an old NESC racer from the '80's, Southwick was always my favorite track. But at my best I was a top C rider, even got my picture in Buckley's Motosport magazine a few times. At that, my lap times at Wick were always faster on my 125's than my 250's. More HP does not always turn into lower lap times, but better suspension always does.
