I have bellowed up pipes installed and my manifolds resealed. The exhaust has been replaced all the way back as well. Today I drove the truck on the hi way and was able to load it up a bit. The egts still get up there but the truck isn't dumping smoke like used to. I AM NOT COMPLAINING! What I would like to know is why? I am curious.

 

You are not loosing boost now, so the fuel is all getting used instead of going out as smoke.