Originally Posted by Velo
Yes but IMHO it is a better designed engine and also a newer engine.
Keep in mind the Northstar engines date years back.
The Northstar was upgraded in 2004 when used in the Bonneville with better piston rings and coated cylinders to eliminate cold slapping and rapping. My 03 Caddy STS was so noisy when it was cold and my 05 GXP is as quiet as the day it rolled off the showroom floor! The 5.3 does have D.O.D. which helps with gas mileage, but it'* not nearly as smooth.....in my opinion.