Thinking about buying the F2 cam from FWD Perf. Says lift is .467, my MP valvesrings #P4286813, -new in the box,- say max lift .460, is that close enough to do? In the past I have takin the M.P. smallblock springs to machineshops, they rate them up to .509 lift, but the machine shop guy checks them, looks at the cam card, shakes his head, cause those aren't enough spring. Just wanted some real world experience, knowing the 813s might be plenty. And since Mp made .460 lift cams, might be why they rate them like that. Or they could be underated? And who's used the F2 cam? You like?