A freinds roadrunnuer, full weight (3800?) 451 with a 268@ .050 race hydraulic went 11.47 through full 2 1/2 inch exhaust. I don't see why a bigger motor with a race hydraulic with as much as 276 @ .050 duration couldn't make 600 hp. I went 10.20s with iron 440-c bowl ported heads, 475 cubes, the same cam as my buddys 268@ .050 .540 lift but had indy dove rockers on it. 750 holley methanol carb. 3180 race weight. Take away a tenth or two for going to stock rockers and you have 10.40s?