We just finished the install on a '05 Yukon, 5.3. We installed an LS6 cam and springs, front mount intercooler, Gt-67 STS, and 8psi.
http://www.trtturbo.com/images/tx_ve...hange_dyno.jpg
http://www.trtturbo.com/images/Texas_Vehic...xchange_004.jpg
http://www.trtturbo.com/images/Texas_Vehic...xchange_005.jpg
http://www.trtturbo.com/images/Texas_Vehic...xchange_003.jpg
I'd say 438/446 was pretty good, especially with 24" wheels.