Problem with Harland Sharp rockers

Thanks for the notice... But like was said, all rockers do that of they are not set up right, OR a larger sping and retainer combo on a taller valve, or a deeper seat, or a set of rocker shaft support blocks is used. Not to mention, at high rpm, the springs are moving around and deforming much more than most think. I'd bet (being one of those who I'm sure you've forgotten more than...) the reason they hit was a non-standard spring/retainer package. And hitting like that, regardless of name, is the builder's oversight. Mistakes happen to the best of us/them.