[Masteryota]

changing with an A12 cam will not require springs, unless you have a racing CDI with no rev limiter, then you would want to bump up to a higher spring rate to keep the valves from floating. Unless you were to swap out the cam with some insane high lift cam like Tom was messing with for the 150's, then head work is not needed. In that case, he actually needed to cut down the valve guides to accommodate the big lift cam.