Yes. It's possible to build 600HP from an 11.5:1 460. It's even possible to do it with just ported DOVE heads. There's an 11 second F150 from Alberta that makes 620 HP on the dyno with 11.4 to 1 and fully ported DOVE heads. Roller cams are even totally neccesary. Ultradyne has a 260-267 degree flat tappet solid with .657-.661 lift that they claim is good for over 600HP from a 460. You need a minimum of 850 CFM, (950 would be better) a Stealth, Blue Thunder/FPP/Probe, or Victor, intake, minimum 1 7/8" headers, either open or with a 3 inch or bigger, no compromise race style exhaust, and a 3800+ stall, if you'll be using an automatic.