A 440 block with a 4.25 inch stroke crank will easily make 500 hp while still having a dead stock type idle. You'll just need to pick the right parts and resist the urge to turn it into a race engine. If you build it like the Chevy 502 or a Cadillac 500 inch engine then you'll have a very smooth performer that will easily take you down the road and give you decent fuel economy and reliability. Just stay small with the heads and cam and you'll be fine. Don't let anyone talk you into a big cam or a big carb.