[hopakco]

Just want to squeeze a little more miles /gal. would a straight through muffler and a 3 or 4 inch tail pipe make a difference?

 

[JeepinOverU]

Yep some people claim 2-3 mpg (w/o cat) but ive never figured it myself. Do turbo back 4 or 5 inch for best results without cat.

 

[IPOLUTE]

If you do 5 inch and you don't have atleast 500hp it will hurt your truck performance