I dont know why you could'nt, but I am almost sure you are not supposed to. It could be maybe because the short duration on a hydraulic cam is too steep of a climb and rapid step down for a solid lifter. The hydraulic spring might compensate for this quick action. I am only speculating now though, just letting my common sence work a bit, and sometimes thats a stretch. That is a good question I think. I am thinking with my solid roller for example, lash is set at .018 and .022, thats not much play for the quick and rapid lobe to lifter movement required especialy at 7000 RPM. remember just talking out my azz at this point.