I have a Comp hydraulic roller in my Keith Craft built Genesis S.O. block, 496 c.i., 622/622 - 252/262.
Very strong running, idles nice at 800 rpm. Dynoed on the engine dyno at Keith's shop at 666HP/638TQ. On the chassis dyno at the shop in Plano dynoed at 560RWHP/550RWTQ. I run a 6400 chip in the MSD box, but all the max. power is in by 6000 rpm's.