FWIW, I run Delo 400 15W-40 diesel oil in my stuff; I'm pretty sure my current 283 in my DD has 300K on it. I also ran it in my other truck with a 250 six to the tune of a quart or more every hundred miles; that one I figure has probably passed the 500K mark. Seems to be good stuff.
Yeah, I know I have a lot of tired old engines; I'm working on it...
Some of my crap:
1963 C-30 flatbed dually 292/SM420
1965 C-10 LWB fleet 250/column shift 3 speed
1965 C-30 9' stepside 250/SM420/4.10 gears (my DD)
Website I made for my crap:
http://www.66submarine.com 
