I am posting a reply to an Email that i got from the author of this article that I got here.http://www.boss302.com/oil.htm I emailed him asking about changing to synthetics and this was his reply (I hope he doesn't mind!): There really is no need for any kind of 'break-in' oil in modern vehicles today. The materials used and the tolerances achieved with the sophisticated factory methods make it unnecessary.
If you are referring ti the Ford 'Powerstroke' diesel, I would recommend a high-quality 'diesel rated' oil. Even though most passenger car oil is rated as 'SL/CF,' which means it is good for both gasoline as well as diesel engines, it is generally only referring to passenger car diesel engines, not the heavy-duty engine in your rig.
Two very highly rated diesel rated oils are Mobil's 'Delvac,' and Shell's 'Rotella.' Both Delvac and Rotella are especially formulated for tough diesel engine duty.
If you want the very best (I know you do!), I strongly recommend Mobil's 'Delvac 1', not to be confused with regular Delvac. Delvac 1 is a full-synthetic oil, such as Mobil's 'Mobil 1.' The benefits of a full-synthetic oil over any conventional 'dino' oil are numerous and well known.
The only drawback to 'Delvac 1' is the high cost of the oil itself, but of course only you can decide what is reasonable for yourself. Delvac 1 is around $5.00/qt. at most retail outlets, and your vehicle requires 15-16 qt. If you are a do-it-yourselfer, that's about $80 for the oil and another $10 or so for the filter.
If you take it to a shop, expect to pay $100 to $125 for a 'Delvac 1' oil change.
Now regular Delvac and Rotella are perfectly adequate, and far less expensive, so the choice is yours, of course.
I would strongly recommend that you use 15W-40 exclusively. Stay away from 10W-40, and 20W-50.
Good luck!

Kit.

I really feel that Kit really "knows oil" and feel pretty safe going with his recommendations!

 

Welcome to FTE!
As you can imagine, this subject has been kicked around a lot. Do a search on oil and you will discover that there are numerous oil PHDs on this forum.
I use Mobil 1 Truck/SUV oil which is the same as Delvac 1 with the same API Service CI-4 and CH-4. By the way, this oil is a 5W40 oil which flows better on cold starts which seems to help this engine.
There are many good diesel oils. Shell Rotella T is a high quality synthetic which I like next to Delvac 1.
As long as you stay with an oil that is certified API Service CI-4 and CH-4 you can't go wrong.
By the way, you should only add 13.5 quarts at change, because approximately 1.5 quarts remains in the high pressure system and doesn't drain.