So my buddy just bought a 2003 6.0L with 170,000 miles on the clock. Its all stock.

My questions are:

I know they need head studs and an EGR delete. what egr kit do yall recommend?

Other than that what are the weak points on these trucks? Tranny problems?
How much power can you add before major things need to be redone?

thanks for helpin out a cummins guy

 

Start with EGR cooler delete, new rebuild kit for oil cooler, and coolant filter, upgraded fuel presure spring ....... They don't need headstuds to be reliable, if you take care those other things first it will reduce the chances of needing studs because clogged oil coolers cause alot of the major issues. Save the headstuds for when they are needed or you plan on going over the 400hp mark, alot of guys swear by the custom tunes for the SCT and if you start with the basics before you tune it it should be nice and reliable. You won't believe the difference in the tuned truck

 

Yep. Agreed with everything Bob said.

Stock tranny will hold whatever power a custom tune can throw at it. The key here is good tuning to keep the tranny alive, so only use reputable custom tuners like Innovative Diesel, GoGo, Gearhead etc.

Other than that, when you say "major" things... to me that means rods, or valvetrain or a trans build etc...

Trans will live up near 550rwhp, depending on driving habits and tuning
Bottom end (rods) will live up near 700rwhp, but have been spun up near 1000rwhp. I just wouldn't expect it to live long above the 650-700 mark.
valvetrain including stock cam, springs, etc has been spun up near 1200rwhp without issue.

He may find he will need a better HPOP being an 03, going up in the big power numbers, but under 500-600 he should be fine.

 

Awesome thanks for the help guys, one more thing he called me and said its been hard to start, like he has to hold on the key for a while....? Any ideas about this? Ill try to get him on here so he can explain further

 

Yep.

Have the batteries load tested FIRST. If one is bad, replace both.

Then, test the FICM. The test procedure is at the top of the page in the 6.0 section.