Hi from a newby in SE Utah. Thank you for all the very helpful advice on diesels. My problem is I bought used Ford F250 HD 7.3 idi from a local rancher. He bought and registered the truck in Calif, then approx 10 years later, re titled it in Utah when he moved here. To the best of his recollect, the truck had around 70,000 miles on it when he had the motor changed out by the IH Dealer someplace on California. He, original owner is now deceased. He was getting pretty forgetful by the time I got the truck from him.the only modification to the motor was his personal friend, Mr Gayle Banks, installed a small turbo unit on it, that being the sidewinder model. Truck now has orig 93,000 miles on it, maybe 20,000 to 30,000 miles on the newer motor. I want to find out exactly when it, the motor, was changed out. This truck was one of 4 he owned and money was no problem. It sat under a large carport most of the time it's been here in Utah. I payed $2300 for it--it's a 5 speed manual with lock out hubs, extended cab, long bed two years ago. Carfax I ran shows no info on a motor swap, the factory warranty was long expired by the time of te engine swap. Appreciate any guidance on tracking down the dates this motor was changed out. Thank you, Old Coasty