The oil feed holes are in a different place. 460 lifters in an FE will pump the pan dry! Crower once tried to consolidate the two. I immediately saw the result when I primed an engine with their 66217 lifter. After some discussion with them, they continued to, and still do, make FE and 385 lifters with the holes in different places. The FE cannot line up with the drilled passage, and the 460 can't face to the main galley side of the lifter bore for the same reason. This will give a direct flow path and oil "to the moon, Alice".