When the #53 block cracked and Cummins put a new short block in the truck we were concerned because we had contracted to move 124 van conversions. Cummins said to just put it to work, no problem. They were aware that the loads were 30,000 plus over a very steep range, they said ok. The truck was driven from Cummins to the trailer and then loaded. A total of 136 of the vans were hauled with the truck running 24 hours. My son drove all day, we switched and I drove all night. We were a week late on the arranged contract and had to catch up. That was 45 loads, non stop except for maintenance and a holiday thrown in. The first few tankfulls were rather pricey on mileage but improved as it went on. The engine went to work with only about three hours of running on it.