Just put in my new GM 350 crate engine last weekend. Drove it lightly on Saturday, maybe 25 miles. Then on Sunday I had to drive to DC from Pittsburgh (250 miles). I stayed between 55-65 mph the whole trip and stopped occasionally to make sure that everything was ok. Pace Parts says to change the oil after 500 miles, which I will do tomorrow. Then they say that the engine is ready for normal use. On Friday, I will be driving back to Pittsburgh. Am I putting too much of a strain on the new engine in such a short time? Is it ok to be driving for 4-5 hours straight without doing any damage?