I have a 2005 yukon and I want to know if I would get better gas milege with a full bolt-on 5.3 or a full bolt-on 6.0.. I think I have 3.23 gears and I know I have a 4.8 with about 100,000 miles..

 

I think that a 5.3 would always get better mpg than a 6.0. But the cost to build either is pretty close. I think the power difference would be worth the few mpg less you would get. A regear would defiantly help out right now. 3.23 seem awful high for something *** heavy as a yukon.

 

Yea... I was thinking I wanted a 6.0 with 3.42s or 3.73s but I do t know yet..