My 340 was fairly stock with a good cam, pocked work, good springs and push rods every thing else was stock. Oh and a little work on the oiling system, 3400 lb car 11.80 115 mph = about 410 hp at crank. With good port work, intake, better cam, and a good set of rods and pistons to hold it together I don' see a problem getting 500 hp. And it was street driven with no problem.