I'll chime in on this. My 360 is .040 over, with forged KB pistons, nominal compression is 12.5. It now has Eagle H-beam rods and very modest porting on iron heads. I'm running a Weiand X-terminator intake, which probably doesn't make quite as much power as, say, a Strip Dominator. The cam is the ancient but effective MP 528 solid, augmented by 1.6 rockers. Nothing fancy for an oil pan. I have 1 5/8 headers, which are probably on the small side.
The original, which I blew up, had an ancient set of TRW slugs which were well worked over to remove weight, but were still heavier than the new KB's. With an LD4B intake, that motor made 450 (well, 447, actually) on the dyno.
From that, I'd say I'm in the 480+ range right now. Next time around, we'll upgrade to a mild solid roller with similar duration and centerline to this cam, a bit more port work, and different intake. Yeah, I think 500 is within reach without going overboard.