So I'm pretty excited got me some rotella t6 5w 40 and rev x one question do I substitute the rev x for 8 ounces of oil or add it on top of the 15 quarts

 

Just add it on top its not going to hurt anything

 

Substitute IMO. Though it's a miniscule amount, I always only use 14 qts of oil anyways. I had always heard when I first got my 6.0 that they were really easy to overfill with oil. I have religiously used 14 qts since I've owned it, so for me I can just add the rev-x without worrying about it.

Though... it probably doesn't really matter, like Jeff said it is a small amount. So if anyone has just added it on top, I really wouldn't worry about it, but IMO if you're doing it all at once, just save yourself the money on that 15th quart and throw it in the toolbox or something, do 14qts and the rev-x.