Thanks, Lar45. I guess I was a little ambiguous. I meant running the 'cat at doubles' pressure, you'd get midrange 375 Wb speeds. Wby can do -what?- 2550-2600 with 300g? Maybe not quite as good as that, but a 300g solid at 2500 would seem to fit the bill. Or maybe a 350 at 2400 or close.

Bwanabe, that's why I looked at 40ksi as a max pressure. The 470 runs in that range and the 500-416 is abit higher. The 500-375 should do about everything that you would want and still keep normal pressures. I was just looking at the 375H&H AI at 40ksi for a comparison to see how much more you could gain with the larger case.