Wyrmrider does have a point in this sense though. The .904 lifter can handle a faster profile ramp. A chevy .875 grind may be on the ragged edge of what it can handle with that lifter but be somewhat tamed down with the bigger tappet. It depends on what someone is looking for. If you don't mind the valve train noise you can get more lift and area under the curve with less duration with the bigger profile. Just like everything else with engine building it is all a trade off.