Most of that gain is in moving to 1.6s, which are available in stamped rockers. I do agree that the factory stamped rockers are weak-sauce, measuring 1.48:1, flexing to 1.45:1, but there are aftermarket self-aligning stamped 1.6 rockers available for about $100, which is less than half of those Proforms. Also, the engine's going in a Suburban, so I don't think it's going to see a lot of 6000+ rpm pulls. If the OP wants rockers, fine, but it's $100 that doesn't need to be spent. Yes, I put rollers in my engine, but if I were building it over again I wouldn't.