Hyd Flat TappetSolid Flat TappetHyd RollerSolid Roller
CostLeastModerateHighHigh
Ease Of InstallSimplestModerateModerateModerate
AggressivenessModerateModerateHighHighest
Power BandNarrowestGoodBroadBroadest
RPM CapacityModerateHighModerateHighest
LongevityHighGoodHighModerate

The next question has to do with the specs of the cam, which is dictated by the actual grind put on the camshaft. There's four key factors here: lift, duration, lobe separation, and the final aspect the actual lobe design, given by the series of camshaft. Herein lies the toughest decision in building the engine-which cam series to use and what specs. Making the correct selection takes experience and an understanding of how the various specs affect the engine's running characteristics and powerband, and interacts with one another. In most cases, the best chance of success is to talk to an expert, be it an engine builder with plenty of experience with your type of engine, or consult with the cam manufactures directly. Comp Cams offers free tech advice on their CamHelp line (800/999-0853). A wrong decision here can seriously set back the combination.

A camshaft requires the rest of the valvetrain to be up to the task to get the most from its designed performance. First on the list is the appropriate valvesprings, correctly installed. Hydraulics can be particularly problematic if the goal is very high rpm, since the slightest false motion will begin to upset the delicate balance of the hydraulic mechanism. Most manufactures recommend specific springs or load levels for a given lobe, and these recommendations are typically a safe bet for most applications. If you decide to stray away from the recommended springs, you'd better have a good reason for making the change, and be prepared for some testing and trial and error before hitting on the ideal combo. Always pay strict attention to the installed height, coil bind clearance, and open and closed load, as installed.