i used a desk top dyno for my horsepower #'s for my motor,i almost did the exact same build except i used a set of ported 452's and used a torker II intake and came up with 475 hp,but i did have a set of 1 3/4 tube headers and the heads had stock valves.according too the program if i had used a bigger set of headers and had the larger valves installed it would have made 520,also i used an 850cfm carburator.That cam sounds awesome,by the way.