thanks to all for the replys i got a lot of great info here. i guess i should have been more specific on the truck, it's lifted on 35in tires and has 4.56 gear already in it and it is a automatic also. it's more of a desert tow vehiclie, then a street/strip truck. if i could figure out how to post a pic i would, but i sounds like i should start with a custom tune, and maybe headers and then a exhust. and then go from there

Has anyone had luck with the JBA headers ? i'm in california and need them to be smog legal.

 

honestly tho for the money you put in a 4.8...it be same price as dropping in a larger cube'd motor.