I think he is referring to being able to stay with the 3" main that the smaller bore engines have (455 uses a 3.25") and that is an advantage for spinning high rpm, but still going for the bigger cubic inches.
If doing an LS you might want to think about going turbo instead of supercharger. You can build way more power if you want to and custom place the turbo for your needs. No belts to keep an eye on, etc.
Or just buy the LS motor I have...its a turbocharged LQ4 block (the one all the turbo builders use), All Pro stage 3 heads built for boost by a professional with turbo and custom dyno tuned computer (800 to the rear wheels, and that was tuned mildly). She was built to handle 1200 hp. Drop her in. lol
I also have my custom built 1200 hp turbocharged 455 for sale in the classifieds here, and THAT is show worthy. Just sayin...lol
http://forums.maxperformanceinc.com/...d.php?t=761839