Can you tune camshafts

Answer 1

Sort of: you could have the profiles of the lobes ground to change the lift, duration, and timing characteristics of the camshaft. It is unlikely that you would go to the trouble unless you were tailoring it a very specific application or set up. More likely, you would install an after-market cam with those characteristics which suit your motor configuration and performance goals. Another possibility is to add an adjustable cam sprocket to be able to adjust the cam's timing (or valve timing).