Oil pressure vs lifter pump up
Why not just switch to a solid cam? I ask this because I am thinking about swapping to a solid just for the same reason. I find it hard to believe that hydraulic lifters don't bleed off a little at the higher RPM's I may be wrong as usual:) I know that the springs, geometry, preload, rocker orientation, and a slew of other calculations add into the big picture. I just like the idea of the solid cam.
No room for mistakes with the solid though, I would imagine that everything better be right the first time or you"ll be buying new parts pretty quick.