Well, lift gives more torque, duration gives more power...
Pick a cam that opens quickly, so its 050" lift figures will be a tad higher than others. They will also be limited in the max rpm from opening the valve open & closed too quickly.
The max lift will depend on the size of the spacer you can put under the shim to make up the heel grind. I have heard of shims flicking out of motors, but I expect it depends on the rpm you're going to use and if it approaches valve bounce or not.
If you're going for mid-range feel rather than peak rpm then the porting job isn't so important.