Your break in time should be the same as a new engine. Now go load it up and work it to help seat the rings. If it wasn't winter time in WY I would tell you to load up a ton in the bed and or hook to a 4-6K tailer and take it on a 36 hour non stop drive (except for fuel) one way to help break it in.

 

If you put gauges on with the mods, how would you know whats normal?

 

You ask here.Cummins is still making the 5.9.Its in use every(08s) where but here in the U.S.