The LS rocker with a roller trunnion upgrade is a hell of a stout rocker. If the geometry is correct I bet that rocker would be stable well in to the 7500 range.
I could see it if you already had Magnum heads, for example. But then again, maybe not. Hughes has those killer shaft mount rockers for the Magnum heads. There's just so many other options besides crappin up a good set of heads with Chevy stuff.