I agree with the cam being too small. So - given that's the case, I don't think you have too much to wory about with this block. It's effectively a rev limiter. I've built several of those 505 kits (512 is a .060 overbore) and they are easilly able to break a stock block if given enough head and camshaft. There's two points of failuer: the main saddles and webbing - which is slow to occur but will ultimately be the end of most high powered builds; and the caps which if left stock will deform and hurt bearings and if replaced with steel will quicken the loss of the main webbing integrity. The best you can do is get it balanced well, do everything to avoid thin cylinder walls and detonation, and if you exceed 600hp I'd go with aluminum caps to absorb some of the shock. I never use a manufacturer's balanced assemblies. I have a shop I pay to get it perfect. If your plan is to exceed 700hp I'd replace the block and I'd go aluminum. I havent shopped for a while for one - so Woofer may be right in regard to finding an iron one. Be aware of "deals" on MP blocks - a lot of them are junk right out of the foundry.