Nissan motorsport used to sell cam blanks but sold out many years ago. I think unless a cam grinder has one on the shelf, they are only doing regrinds which can be much less stable at high RPM when not setup by a professional. You end up using a much thicker lash pad and a retainer with a much deeper cup to support the pad. This also means you will have to run a spring package that is around 240 lbs open pressure. Your cam grinder should have this worked out and have some packaged offering with springs and lash pads. The lash pads should still be checked as they can only be ball-parked due to them not knowing the exact installed heights, whether or the spring seats have been cut, valve length due to stem resurface, etc. Springs are relatively cheap and should always be replaced when a cam is upgraded. I find this is the best advice as most guys wont have the know how or tools to properly setup the springs and check for coil bind without hurting the spring.
The real lesson is, never throw away stock cams and it may be your only ticket someday.
I know, long winded but I hope this is helpful.
Steve