The fact is that anyone who says that you can operate an L31 with stock components and a 0.470"/0.480" lift lobe, simply has not taken running clearance into consideration. You will need 0.050" to 0.060" clearance between the bottom of the retainer and the top of the valve guide seal as a safety clearance. The guys who run with no safety clearance are just newbies who have not seen the havok that can be wrought and are just asking for trouble. They will learn their expensive lessons sooner or later, just like the rest of us did.
.