Camshaft Assistance and Translation Options

[Mockmaw]

The camshaft is the last component of my rebuild that I haven't decided upon yet. I'm trying to learn what I can about them so I can make an intelligent purchasing decision. Yes, I know this is a broad topic..

I don't understand the relationship between duration and lift.. what running aspects are changed as a result of increased duration? What aspects are changed as a result of increased lift? At what lift and/or duration should I worry about longevity issues?

There are so many numbers out there and the descriptions that go with each camshaft seem too vague. I can stare at the webcam page all day and still not know how different an 86 will be from an 86a or 86b.. or 494, etc etc etc. Can anyone help me or point me towards some resources that will help me translate these numbers a little better?

Thanks!