Finally got around to looking deeper into it and found that the "F" stamped cam is for a P79 head. My car is a 1978 280Z with an N47 head along with all other N47 parts. My question is, are there any advantages to the PO doing this or is it something to not worry about? I have the valve lash adjusted to what called for in the manual.

Maybe he change the cam and used the old one as a core deposit? If its a mild cam you might not notice the differance because you hve not driven the car before the change over.

To change the cam for a standard P79 cam seems a lot of money and effort for little improvement.

The specs are here http://www.xenons30.com/cams.html