Also the Gen IV big block was available as a crate engine. It was a little better than the originals, which are generally long since picked clean in wrecking yards. I think it's up to Gen VI now, and you can buy a crate 502 from Summit racing, carb to pan, for $14,800. It makes 580lbs/ft of torque, which is very doable with a near-stock Cad 500 using a modern camshaft and light cylinder head port work, for half that.
