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Old 10-15-2012, 02:37 PM
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Originally Posted by M.Rydell View Post
Heads can handle up to .550 lift. Forgot to write that
Are you talking about the ability of the springs to handle that much lift, or are you talking about the heads being ported to flow well at 0.550" lift? The stock ports are all done well before then. So adding lift past the point of max flow really won't get you more power, it would be the added duration that would help.

Added duration helps at a higher rpm, provided the port doesn't become so turbulent at higher rpm that the power is hurt instead of helped. But at the same time, increasing duration costs low end power, all else being equal. In a street driven vehicle, keeping a strong bottom end helps a lot more than peak power output. Look at it like this: you will see the lower rpm range every time you pull away from a stoplight. You may not see 5000 rpm a half a dozen times a day, if that, in ordinary driving.

The ideal cam would instantly open and close the valves. Obviously, that cannot be done w/the production valve train of a SBC. So the closer to instantaneous valve action you can get will give you more power under the curve. That's where the XE and Voodoo cam grinds come into play.

The XE cams have gotten a lot of bad press due to wiped out lobes and noise, but for the most part- as long as the cam is installed correctly and everything is checked carefully, they will not fail any more often than any other high performance flat tappet cam, and they will make good power. If I were going to run a flat tappet Comp cam, I'd seriously consider having it nitrided by Comp, anyway.

If at all possible, run a roller cam and matching springs.

Good luck.
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