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Old 01-07-2013, 04:21 PM
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These are really different cams in terms of duration. The lift is only one component that needs to be looked at. Duration has a huge effect on where the power band will be much more so than the lift. The other important component is Lobe Separation Angle (LSA) this is a place where small differences add up to radical and substantial differences in operating behavior.

The Summit cam has an intake duration of 292 degrees at zero or maybe .006 inch lift while having 234 degrees of duration at .050 inch lift where the Howards is 266 degrees at zero/.006 and 213 at .050 lift. This analysis will also fit the exhaust side. But the intake provides much more effect on where the power peaks will be because of where it closes the intake valve in respect to how high the piston has raised in the bore. The Summit cam is a very old fashion lobe shape that holds the valves open a very small amount for a long time. This allows the compression pressure to leak back into the intake until enough velocity is built up within the intake flow to overcome the reverse pumping of the piston against the late to seat intake. This radically pushes the power peaks way up the RPM range and requires a lot of compression ratio both static and dynamic to restore the lost bottom end power. This line of thinking was adequate in the muscle car days but today is incompatible with unleaded premium fuels. Cams today need to act fast, get the valve open, shove it high off the seat and get the damn thing closed. This Mickey Mousing around with long slow ramps is so yesteryear and ineffective today. These old cams are a waste of money, they don't produce the power you want and need nor will it be where an engine short of a competition motor can use it and they guzzle a ton of gasoline while giving you these operating fits. The cheap to buy cam is not the answer as it will cost you in spades down the road in fits, fuel and wear on the cam and lifters.


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