I discovered this forum when researching oil usage in the purchase of my, new to me, truck. I had no idea there was a whole sub-culture of oil geeks out there. I just bought 1998 3/4 ton chevy 4x4 truck with 110,000 mi on a 350 engine. I am the third owner. The first had 100,000 hwy in 5-6 years. The second had 10,000 in 10 years. Both minimal towing. I will use it bomb around town on occasion and pull my 34' fifth wheel camper a few times a year. In recent years it was not driven much but run once a month or so, warmed up good, driven 30+ miles and the 4wd engaged. Kudos to him for keeping it up. I am aware using oil is very common in this motor and not worth loosing sleep over. He said it maybe used/burned 1/2 -3/4 qt per 3000 miles. He ran castrol conventional 20w-50 in it. Not sure why? I think it was just some old school thinking or something. I bought it in Springfield, MO. Before driving it home I changed the oil in his driveway with castrol conventional 5w-30. Now with 600+ miles on the oil of mostly hwy taching 2400rpm the oil level has not moved...maybe a 1/32". Might not use as much as he guessed. My thought was run some thin oil through it to "clean it out" then switch to what ever my heart desires. Also maybe change just the filter, or oil and filter at 1500mi the first couple times. I am taking it up north next week pulling a small boat with the fam. 750mi round trip. I will start a new thread later about which oil, filter, etc and how i drive it. Just interested in "my break in process." Thanks a bunch!