high rev with hydraulic lifters ? what are the rpm parameters, I would think the stock system would support 6500 with the right valve spring, lifter and oil capacity. :)
7200 and up. Never used a hydraulic in anything like that. Always solid rollers. Any mods I've ever done (or not) were for the purpose of keeping oil on the crank at high RPMs to avoid starving the bearings. That is the priority.