So I recently built a 460 for my bronco, and I have about 150 miles on it. I always use to use chevron delo 15w 40 diesel oil because of all of the additives in my engines but even they have removed the additives. My machine shop had me use joe gibs breakin oil, and they recommended that I use joe gibs motor oil as well. Its like $7.50 a quart for that stuff. They said that I could also use valvoline racing oil because it still contains the additives. I could only find it in straight 50 weight or 20w 50. I use to use 20w50 on my old worn out 400 to help maintain oil pressure but what are your thoughts on useing it in a new motor. BTW Im running a high volume pump. Thanks and sorry for the long post.