I realize that it is counter intuitive to think that you can put a stock profile on a stock cam by removing material. I also doubted that it could be done even though all cam makers say they can do it. I spent a lot of time doing research with the intent of proving the cam makers wrong. Something HAD to give.
What I found was that something DID give. Valve clearance had to be adjusted. Most commonly done with adjustable lifters on our flatheads and with adjustable rockers on overheads (sometimes with longer push rods and sometimes by machining down rocker stands if so equipped). That's it.
Here's one more try at an explanation...
In this image you can see the effects that a worn camshaft has on lift, if it is worn by 0.020" then it will have that much less total lift. To calculate the lift you measure the width of the lobe and subtract that from the height. By removing that same 0.020" from the entire perimeter of the lobe, keeping the same centerline, the entire lobe is smaller but the effective lift is restored to 0.400". That 0.020" now can be made up with the extra preload the factory gives hydraulic lifters, or on a solid lifter valve train you just reset your clearances.
http://www.coltcams.com/html/tech_tips/
I think it's healthy to doubt. I do...all the time. I did on this subject. The bottom line, however, is your opinion must be supported by facts in order to be substantiated (well, at least on engineering subjects
). Making it true by saying it's true doesn't work. If you believe that a stock profile can not be ground on a stock cam (like I believed at one time), then do some research and link to some facts from credible sources that support your belief. Your opinions and thoughts are interesting, but won't win debates.