I've read the chapter on cams and valve trains two or three times now and still have a couple questions. He does a great job of explaining the theory behind everything but doesn't explain HOW to determine cam characteristics especially duration. I was searching here on HybridZ and found a post by Pete that says you can use the equation "duration=2*[(overlap/2)+LSA]" to find duration but when I tried it for what I thought was a reasonable overlap and LSA I got a very high duration. Here's what I was thinking:
D= 2 x [(35/2)+108]
D= 2 x (17.5+108)
D= 2 x 125.5
D= 251
That seem way too high, especially with what Pyro was saying above.
Also, he covers lift but doesn't tell how to determine maximum lift. He just says run the most you can. Is .500-.510 reasonable?
Thanks for all your help, I really want to understand the how and why behind this stuff rather than just be told what cam will work.