Stock used Magnum cams are plentiful. That is the best way to do a regrind, as long as you not looking for something “really big.”
What kind of application are you looking for intended use?
I am considering to build this 360 magnum as a short block / back up to my current 340 race motor, in the event that I needed it. A lift in the area of .600 for starts and probably change pistons as well to get the Magnum in the same 450ish HP area.
The 340 has early EQ Magnum heads ported and magnum RPM AirGap. This is more of a back burner build but I'm doing some homework to see what I would need.