Synthetic oil mixed with dino oil question

[bogeyb]

My buddy has 4 Qts. of CH-4 Amsoil synthetic 15w-40 oil that has been on the shelf since he sold his 7.3L, and he now has a 6.4L 08. He doesn't want to use it on his new truck and I am wondering if it would work on the 6.0L mixed in with motorcraft 15w-40? It seems a shame to send the oil to recycle. Will the CH-4 oil mixed with CI-4plus have any detrimental effects on the 6.0L????

 

[bbslider001]

It would probably help that engine if anything.......

 

[Pablo]

He could sneak in one quart per change and have no issues.

I'm a little confused by your post, though. His truck needs a CJ-4.