Before I recommend a cam, I'll need to know tire sizes and gear ratio's. Once I have that, I can answer your queston.
No matter how much material you take off the head, you'll never move the piston closer to the head to acheive quench, all you'll do is increase the compression. Don't confuse compression and quench, they are completely different entities.
Ask away! That's what I'm here for. :) BTW, the power doesn't just drop at 4800, and it will pull to 5200, it just flattens out after 4800.