My 51 1-ton was working on its second engine when I got it in '71. The odometer showed in the high nineties. The engine, a 48 babbitt beater 235, was built with care by my buddy's grandfather who was a machinist at Pacific Car and Foundry (KW) in Renton, WA and bought the truck new. He drove it 25 miles to work every day. When I got it the 235 needed a valve job and the rods knocked. By '73 I'd pulled a full pressure 235 out of another truck I had and rebuilt that. It's in the same 51 1-ton and is still running today with about 180K on the clock, though a year ago last fall I put all new bearings in it -- badly needed but it didn't knock. Amazing the difference full pressure oil and high quality oil makes. Also there's not much dust here but plenty of mud.