87442lover got most of the info about the lifter but there is a tad bit more. As the lifter gets raised by the cam lobe the piston in the lifter gets pushed down and will cover the oil hole in the side of the lifter and not allow any more oil to get back out. In essence you now have a solid lifter because the oil will not compress so the push rod then pushes the rocker which opens the valve. By tightening the adjustment up that extra 1/2 turn you will cause the valve to open just a fraction sooner, hence you get that seat of the pants good feeling because the throttle response is RIGHT there RIGHT NOW. The down side is if you over rev the engine like miss a gear then you could "float" the valves which then might give the top of the piston a little kiss. Because the valve stays open when it should be closed.
But to answer your question, no you do not get more lift from the cam grind you just get it's lift working a little sooner.
Chevy engines you can adjust but Cadillac engines are non-adjustable so if they are too tight or too loose then you have to buy different length push rods to get the lifters in the middle of that lifter piston travel. A lot of Fords are like this too. You just torque the rocker and the lifter takes care of itself.