Edelbrock sells a hydraulic roller G2 Hemi camshaft, that they claim supports 700hp on a 528 with their heads. Typically hydraulic lifters aren't used much in serious hemi engines because the valve-train is super heavy and the lifters don't work well, rpm is limited etc. I had a somewhat mild solid roller ground for my 540 Hemi (not running yet) and I'm hoping a melonized gear will function well with the steel cam core. I plan to drive it on the street a lot.