I kind of wonder if you doing a micropolish treatment to the rockers would help to increase the stock rockers capacity. I know this treatment helps to eliminate stress risers so you would assume that would help them perform beyond the current rpm capacity. I'd also be curious of their raw strength as well so that you know where the current rockers weaknesses are. This is where putting stock rockers on a spintron would be beneficial to see where the happy rpm cap is.