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Dtype38 - yes you are quite right - two small valves offer much more aggressive opening profiles compared to opening one bigger heavier valve....in short - drastically less inertia to overcome.......this gives more area under the complete lift curve, more area = more power........for a pair of 35mm intake valves the flow pretty much maxes out at 12mm of lift, which is about 30% of the valve OD as a guide........the trick with a good pair of race cams is to open the valves as quick as possible, hold it open, then close them as quick as possible........this is where the combined inetria of the valve, cotter and tappet all come into play.........this is why finger followere are standard fitment to all F1 engines, the reduction in inertia of a finger follower compared to a tappet is about 30% reduction........not to mention less friction.........some of the race cams I have seen have been very "square".........generally speaking your kicking the proverbial out of the valve train. this is also why titanium valves need to be titanium-nitrided in order to give them more wear resistance.........and full race spec tappets and finger followers are now DLC coated along with the cams........they really do take a pounding on a proper race motor.
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