I have an 03 3500, early 03 i believe, it had no cat on it when I bought it. So far I straight piped it, still the 3.5", took the cone out of the turbo, has a edge chip on it,I assume a single stage juice, has no way to change the levels on it. A Banks intake on the way with a ram air scoop. This truck is my pulling vehicle, I go through quite a few hills with around 15,000 behind me, and mostly flat ground when I have my backhoe behind me, pushing 21,000lbs. The truck pulls great, and doesn't heat up. I am looking for gauges also of course, but in the meantime am looking to upgrade the turbo also. Read lots about the Garret 3 stage and an HE351. Anything I could do to the stock one to help out? Any help appreciated.

 

The stage 3 is a little large and has some surge issues for people without a cam. The 351, I wouldn't waste my time. It still has the little 9cm exhaust.

HTT 62/65/12 will help you out.

Best thing to do would be call Fleece, E.D., or Forced Induction. And get a custom turbo built specifically for your needs.