I was wondering what the numbers refered to when buying a cam. I'm guessing one is lift and the other is duration. Any info would be appreciated. Thanks!

 

Duration is the is the 3 digit, non decimal numbers (ex 234/242). Old school guys used the advertised duration, but a better number is the .050 number which you will see 99% of the time around here.

The lift numbers are the ones with decimals .575/.575 lets say. That is lift at the valve, not at the cam. Most of the time it is measured with 1.5 rockers, but sometimes 1.6, just read carefully.

The LSA is the last number (ex 112). This will determine overlap, powerband, and idle. Super simplified, but thats basically what it does.

 

Thanks! The duration, is that in degrees? Is the first # the degree that it opens, and the other one the degree it closes?

And I'm guessing the lift is in inches. So that means that the max distance the valve will open with 1.5 rockers?

What does LSA stand for. Is that take into account the rate at which it lifts and closes therefore determining idle, power band, and other characteristics.

The last thing, could you give me a full example of how to write out the specs of a cam. Thanks!

 

If you look at the beginning pages of the Comp Cams catalog, you will find lots of general cam info.