GM's Vortec V8 platform is absolutely brilliant. I've had extensive experience with non-cylinder shutdown Vortec V8s, to include a '02 Silverado 5.3 with 196K miles, a 2004 Yukon XL 5.3 with 267K, my daughter's 2006 Envoy Denali 5.3L 140-ishK, 2003 Cadillac Esacalade 72K. All have 3.73:1 gears...