When I fist bought the truck, it smoked pretty badly. I eliminated the "Jet" valves and the smoke decreased but was still there. I changed the oil and filter which helped.
I was sent out to a new assignment in Carson City, NV, so I drove from Sacramento to CC. The truck ran super and ran 75 MPH most of the way over the mountains loaded with about 600 Lbs of my crap.
No more smoke!