Personally, I like the 400 block as it leaves more room in the engine compartment and for all the world a 500" low-deck looks like a 383; guess that's the old secretive downplayer gene in me. My last 2 BBMs were 440 blocks in early B bodies, and they were a pain to work on on the right side.
Another thing I like about the 400 block is the bigger cylinders help unshroud the valves/flow a bit.
Your situation may well differ, and it's just my opinion. Next BB I want to build would look like a stock 383 Road Runner but lays down 11s through mufflers...
Shouldn't be hard to do. A low deck 470 with Stealth heads and a Performer RPM would do the trick. Squirt everything with factory engine paint and a lot of people won't know it isn't stock. The HP manifolds will easily support enough power to run 11's, the key is getting the correct cam and compression. A Holley will work or run a 800 cfm Eddy carb for more of the stealth look. You can easily make 550 hp with a setup like that and it will idle smooth and run on pump gas. That is enough power to run low 11's if the car isn't a complete tank and it can hook up.
