cam stamped numbers

I just picked up a 1975 280z parts car. Once I got it home I pried the hood open and found a set of dual carbs and a 6 int 1 header, the fuel injection had been bypassed. I removed the header and intake to find a f54 block and a P90 head. So now I am wondering since someone had gone to all this trouble years ago, I would like to know if it is a stock cam. The numbers on the end of the cam are 270.60, does anyone know if these are stock numbers?? Also, how can I tell if a head has been shaved, is there a measurement I can take with a depth guage?
Thanks for any help