American Pie
You can use a stock 460 block with 2 bolt mains for up to around 600 Horsepower as long as it's not supercharged or has alot of nitrous. Add main studs and a stud girdle and you are ok to about 800+ horsepower. If you internally balance your engine there will be less stress on your main journals. Also try to get the weight of your rotational assembly as light as possible. Your engine will rev faster, and the rod and main bearings will last longer. There are several manufacturers of lightweight rotational assemblys. Try
www.scatcrankshafts.com and
www.crower.com another cool site is
www.roadsters.com. Hope this helps.