600 HP and 6,000 RPM should be good with stock caps and ARP studs.

When I started my 500 'B' block I got the BCR caps/girdle because I originally intended to go with 350+ cfm ported heads, a tunnel ram, and a biger roller cam to try and make 750+ HP and 7,000+ RPM, but I toned my goals down a bit with a single plane intake and a milider cam, so I only expect to see about 700hp and 6500+ RPM.

The old 451cid engine using stock caps was fine at 580 HP @ 6,100 RPM, but I chassis dynoed it a few times up to 7,000 rpm with no problems.