I'm just wondering if there is a downside to a hyd roller cam as opposed to a hyd flat tappet in a BBC. Is price the only reason not to go with a roller? Performance and durability seem better, but maybe I'm missing something? Thanks for the insight.

price and a little added complexity in setting up the thrust clearance on the cam. Most rollers have substantially more lift than similar duration hydraulic or solid lifer cams. It's up to the engine builder, the guy who actually puts it together to make sure the rest of the valvetrain is up to it.

Tom