Had to say. They say wait for 500 miles due to the rear end but then hook up a trailer and start pulling. I also have read that the exhaust bolts that hold on the manifold should be a slight color compared to burnt or looking new. That is one way to tell if motor is getting warm enough to break it in. I don't haul or tow and mine looked good after 45,000 miles on the truck. Before then, only a few looked like they were toasty.
