Everyone I've talked to says that. But at the same time I know how much everyone loves to overestimate their power. There are lots of 400 horse "500 horsepower" engines out there. So I figure, aim low, hit high. Going to do max port on the J heads I got on there, with existing 2.02/160 valves. Port and match work on RPM airgap intake that's already on there. Then spec a custom solid roller, match my compression to get around 8.5-9 DCR (we got 94 octane here). And see what happens.
That's an interesting idea. There was a guy around town here about 10+ years ago. Ran a destroked 440 (I think he said it cubed out at 393 or something, it's a long time ago). Dropped an 8-71 on it. And regularly pushed it to 9k RPM. What I heard (full disclosure I wasn't there) was that he was in the local hangout parking lot one night honking on it, pushing it to 10,000 RPM and it pulled the custom billet crank apart.