There was a significent lip worn on the top of the cam.
The gentleman reground the cam to the same profile (i hope) and removed the lip.
Metal is also taken off the base of the cam so the lift is the same. The difference in size is taken up by tappet adjustment.
Nitriding is just the modern version of case hardening.
The whole thing costs less than a new one and should be better.
Unfortunately David, I don't have another cam to trace, hence the inquiry.
and Josh, one day you might use some of this technology when you upgrade to a cessna (or victa?)
cheers