Harlon sharp roller rockers

Yeh I always thought they were good to an have never had any problems in the past. The rockers are not hitting the springs. I know the angle on these is terrible so I have been going through the valves after every run. This is a 392 stroker moter with w2 heads. I got 651 horses on the desk top dyno but that is just a guess. I am running a 630 lift cam with quite a bit of spring pressure. I am running it in a sprintboat. I turn it 6500 for about 60 seconds. Am I expecting to much? Is there a better rocker out there?