Choosing the right cam

Hi Chuck. On a TBI system, i'd look at a minor split duration with the intake in the 210/212 @.050 range and a 114/116 LSA max. Since it's a computer controlled deal, you have to keep things tight for a good vacuum signal.

How do you come up with those number though? I'm not putting a cam in anything. I'm just trying to get a better understanding of how to choose one in the future.