great video about different carb/intake setups on a 5.3 LS motor. Look around at the other videos they have, very informative.
http://www.carjunkietv.com/watch-shows/suck-squeeze-bang-blow/GMPP-LS327-Carb-and-Intake-Test.html
http://www.carjunkietv.com/watch-shows/suck-squeeze-bang-blow/GMPP-LS327-Carb-and-Intake-Test.html