350 Marnum cam I.D.
 

I picked up a 350 Magnum engine, built up and now have questions about the cam. I am suspicious that the cam is not stock Mercruiser for Marine application.
Without tearing the motor down (becaude it's installed) is there any way to get a rough idea of overlap,lift, cam timing that might be a clue. Would a degree wheel help?
I am like Clinton, I don't want to inhale.
The builder can no longer be contacted and I am suspicious of some of the work done on the engine.
It is set up with a QuadCarb and EMI Thunder headers.