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Old 09-24-2009, 12:01 PM
blykins blykins is offline
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David, we can talk about it further, but that 236/242 cam on your engine wouldn't make the power with the Performer RPM heads as they would with the AFR heads that I used on the 347.

With a lower flowing head, you have to make up the power with the camshaft. That's why you were having to get up into the mid 240's duration to make the power you were making.

If I were to spec you a camshaft, we'd discuss where you wanted peak hp to be. I always cam to make the most for the rpm range that you're running and then the horsepower kinda falls where it falls. The reason being, if you're reaching for a certain hp number, then essentially you're overcamming to make a number and then you deal with hp rpm peaks at slightly unusable levels, plus a finicky bottom end, more maintenance, etc.

I put quite a bit of emphasis on .050" duration and LSA. Then I look at advertised durations to determine how wild I want the cam lobe ramps to be and to check dynamic compression ratios. The closer the .050" and advertised durations are, the steeper the ramps are, and the rougher it will be on valvetrain components.

If you keep the same heads, same compression, and same displacement, then a smaller cam is going to make more torque, but lower the horsepower and the peak hp rpms from where you were before.

I can make more power than you were making and still keep the level of driveability and maintenance that you were getting before.
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