Cam re-grind

So I am still looking around for a new cam and lifters for my slant build up for a valiant wagon.

I almost went for a new Comp cams unit from Summit racing as they are readily available, but then I started hearing push back about the oil pump gear being too hard and eating up oil pump gears and causing engine failure.

A few people have told me to "regrind" an original cam for better results.

I started asking RRR about it but I am still not clear so I decided to bring it over to FABO in case anyone else has the same question. He mentioned something about putting a cam lobe on, so are the lobes removable?

Maybe my thinking is wrong but it seems to me that if you "regrind" or "grind" a piece of metal, less material exists than previously.

So if you have a worn cam and you grind material off, then you have a cam with specs worse than a worn cam.

I am sure there is something I am missing??

any Cam gurus out there who can explain this ?