Being a bit of a novice I was watching my buddy install a new cam into his big block 396 this weekend. He put a summit 540 lift 228/238 at .050 114 lobe seperation. He installed it 4 degree advanced with the wheel. I understand that by advancing the cam you help bottom end, but by advancing the cam 4 degrees how did the above numbers change. Is there a formula.

Those numbers didn't change at all. Overall length of time that the valves are open doesn't change. Advancing the cam refers to when the valves open and close in relation to crank rotation. Meaning that the valves open (and close) slightly earlier than they would if the cam was installed straight up.