I understand that the best method for choosing a cam is to use your head flow numbers. My question is: how do you do this? How do you tranfer head flow numbers into a cam choice? Thanks in advance.

 

While I think Fred or Rich etc. could explain better, I'll give it a whirl.

Your head flow numbers give you two important pieces of info. You find out the valve lift where you get peak flow, and you get the actual peak flow number.

The peak flow number will tell you what kind of rpms your heads can support on a given displacement. Knowing the rpm range you can support will help determine your duration numbers.

The valve lift where peak flow occurs should be where you attempt to have your cam lift ground. That way you are not opening the valves more than needed(past head stall point), but you're also not leaving power on the table by not having enough lift.

While there are more factors involved, that's it in a nutshell.