I know aluminum is supposed to have a finite work life but a late friend of mine had a set of Crane Gold rockers on a 440 he built in the 70's with a Crane SS305 cam in it. He put just over 200,000 miles on that car over 25+ years before he redid it with SR heads. I'm not sure but I think those rocker arms are still on it with a 535 lift Comp in it.

Kevin