Roller Vs. Flat Tappet Camshafts, 302 Ford, 351w Roller Cam Conversions

Advantages / Disadvantages	HYDRAULIC FLAT CAMSHAFT	HYDRAULIC ROLLER CAMSHAFT

BREAK IN TIME	15-20 MINUTES	NONE
COST	LESS	MORE INITIALLY
PEAK POWER	GOOD	GREAT
CAN REUSE	NO	YES
EFFICIENCY / LONGEVITY	More frictional Losses as RPM is increased	LESS FRICTION
POWER POTENTIONAL	GOOD	BETTER WITH LONGER TIME SPENT AT HIGHER LOBE LIFTS
IDLE QUALITY	Usually not as good because more Duration and Overlap are required as a trade off to gain more Horsepower	Better because cam doesn't need to have as much duration or Overlap to get More Liftt
Cylinder Head Spring Pressure	IF Too Much Pressure and can wipe out a camshaft	Can handle More Spring Pressure being that it Rolls over the Cam instead spinning like a top. Spring Coil Bind still needs to be checked no matter what Cam is used!
POWER BAND	Good	UP TO 1000 RPMS MORE THAN FLAT TAPPET DEPENDING UPON APPLICATION

There are two basic categories among camshafts; flat tappet and roller. Flat tappet cams are the ones most people are familiar with. Most engines in the muscle car era came standard with a flat tappet cam. The tappet, otherwise known as lifter is, for the most part, flat on the bottom. Oil is the only thing between the lifter and camshaft lobe preventing them from welding each other together. Eventually, the cam lobes can wear down to a concave shape rather than the convex shape they started as. This causes the valves to not open or evacuate the charge of air and fuel. Loss in power and efficiency is the result. Roller camshaft lifters actually roll over the cam lobe. The results are a much longer lobe life due to a lot less friction. Roller cams also have a great performance advantage over the flat tappet. The faster you can get the intake valve to maximum lift, the longer it can stay there before the piston comes rushing back up the cylinder to compress the air fuel mixture. If the goal is to load the cylinder with as much air and fuel as possible, the longer you are at maximum lift the better. Flat tappets need a smoother transition from the base circle of the cam to max lift, leaving less time for the lifter to dwell there. Roller lifters, on the other hand, can survive a much more abrupt transition resulting in extra time at max lift. If you compare a roller cam lobe to a flat tappet lobe, you can see the roller cam has a larger radius at its peak, holding the lifter at max lift for a longer duration. A major limitation of the flat tappet is they can only tolerate a limited load between the cam and lifter before wiping out. . In fact, with light spring loads, a flat tappet has a very long life cycle, but at high loads, its life is reduced, and there are definite limits on how much spring load can be applied. With very aggressive profiles, high-lift, and high-rpm, more spring load is typically needed for valvetrain control, and a roller becomes the natural choice. All modern day cars have roller setups. No need to break-in a Roller Camshaft vs. flat-tappet cam, that does and the virtual assurance of avoiding premature cam failure. The flat tappet cam has been in use for a long long time with success but can't compete in longevity and performance of the Roller Setups.