Overlap?

[6.0vortecchevy]

As I understand what overlap is. What i don't understand is the difference between positive and negative overlap. I put my cam spec in and i got -50degrees of over lap, now i put a another cam spec in and ill get like positive 40 degrees over lap. If someone could just tell me the difference between the two that would be great. thanks

[RUFFNECK]

Here's some info I found that might help ya bud... http://www.ls1tech.com/forums/genera...cam-guide.html