Not sure who you think the RHS heads are aimed at but to me, they are marketed as a street machine head for guys who want 450hp or so. Even that level might be a stretch with the valve spring issue. This is what makes the other heads look like a better deal until they figure out the problem.
That being said, if it were me and I was planning on using a cam with .620" lift, (which assumes you're looking for at least 525 + hp with a small block) there's NO WAY I'd even consider using these heads with their inherent flaws, you'd be swimming upstream. At a minimum I'd be looking at W2s. Indy aluminum would be a good choice too, basically anything with an ALREADY offset rocker, 2.05" valves and on and on.
Right tool for the job is all I'm saying. But hey, what do I know, I'm just a guy on the internet.
