Getting back into the game

Hey everyone. I'm a 20 year otr driver. I drove mostly as a company driver. I left for 2 years working in the oilfield but am going to come back as an owner operator. I'm picking up a 1998 volvo 770 with a cummins n14 550 hp engine, rebuilt at 400,000 miles. It now has 780,000 miles. Just wondering if you guys can give me any insight on this truck and engine that i should be aware of. Any positive or negative experiences would be appreciated.
Thanks!