ok so i have been around old cars and stuff my whole life but thats not very long only 18 years. but anyway i was hoping someone could help me out with what the different cam specs really mean and what effect they have on performance.



-duration-im assuming this is the number of degrees from fully closed to fully open and back to fully closed of the valve, is that right? what does varying values of this mean as far as how the motor runs.



-duration at .050?- where does this number come from? is this the number of degrees the valve is open greater than .050. so the bigger this number the longer the valve is open? whats good about longer duration whats not?



-valve lift-i realize this is how far the valve is opened but what affect does varying this have, whats the advantage of more lift(more air flow?????) whats the advantage of less lift?



-lobe separation- i assume this the number of degrees from center of one lob to center of another lobe, right? so what that really mean in the performance?



thanks if any one can clear up this puddle of mud for me so i can actually just look at the numbers and decide on a cam for any particular project i may be doing instead of having to use the trail and error method.

I've got this article marked on my computer - so everytime I think I know something about cams, I can be humbled.

Vizard is a smart dude - even if he likes chebbies ........

http://www.popularhotrodding.com/tech/0607phr_camshaft_basics/index.html

 
 Steve Metzger       Tucson, Arizona

Hello Flatbedford guy. A much more IMPORTANT BASIC fact is that a solid lifter cam like a Yblock REQUIRES ZDDP additive in the engine oil if it is to survive. No ZINK no cam lobe. Read up on ZDDP on google. Good luck Pete