You might find an answer here but the people you really want to speak to are located at
PTCrew.com - Learn it or Burn it. It's free to join and register. Most of the members are into speed and although there's mostly talk about turbo's, I'm sure there are owners that have taken an N/A cruiser and threw some money at it to beef up. You might find that just throwing in a cam is not enough and a few other modifications are needed. Oh, and watch out for the tranny. It's a weak link even without modifications to the engine.