Page 8 of Lunati Camshafts by Holley Performance Products, Inc.

cams flat tappet or roller manufacturers and racers have used flat tappet camshaft systems over the years with great success however manufacturers and racers favor roller tappet cams when rules permit their use because roller cam designs have distinct advantages over flat tappet designs valve train friction sliding frictional forces are higher than rolling frictional forces therefore a roller cam takes less horsepower to turn and generally does not wear out as quickly an added benefit is that roller tappets do not require replacement when changing cams and if pop-up solid roller tappets are used such as p/n 72400lun the camshaft can be swapped without removing the intake manifold profile if a cam profile has more area under the curve it has the potential to make more power roller profiles can be more aggressive and accelerate the tappet more than a flat tappet profile flat tappet profiles can only be shaped up to the point where the tappet digs into the profile roller tappet profiles are not limited by this condition-so much that even inverted radius profiles are possible this benefits engine performance in two ways more tappet lift can be achieved without the added duration that would normally be required to ramp up a flat tappet to the added lift-making the lift curve more pointy the lift curve can be made broader without increasing lift of course both of these benefits can be combined to create a profile that can easily outperform flat tappet cams pistons flat tappet lobe vs roller tappet lobe flat tappet lobe roller tappet lobe 0.350 roller tappet cams can accelerate and give the tappet more velocity than a comparable flat tappet cam of the same lift resulting in more area under the curve 0.300 0.250 rods lobe lift inches 0.200 0.150 0.100 0.050 cranks 0.000 flat tappet with roller profile roller tappet with roller profile engine kits cost unfortunately roller camshaft systems cost more than a flat tappet cam and lifters much of the added cost is due to the lifters however roller tappets can be re-used where as flat tappets cannot not be re-used if you tear down your engines frequently the rollers can be used over and over again provided they are not damaged or show signs of wear the edge of a flat tappet will dig into the ramp of an aggressive roller tappet profile apparel tech line 662-892-1500 9

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