Very good MPG information
 

Now don't anyone have a hissy-fit because the C word is on the document. Everything stated there sounds legit to me; it is aimed at tractor trailers, but the theories should apply to our trucks also. And I just put traction tires on the rear- oh well.

http://www.everytime.cummins.com/assets/pdf/MPG_Secrets_Whitepaper.pdf

Interesting reading. I have an ISM cummins in my tractor. Learned some tricks that I'll try tomorrow. I was surprised to read that there was virtually no difference between dino/syn oils for fuel mileage. Offhand, I don't know what the optimal rpm's are for cruising speeds on a 6.0.

Yep, interesting read. It's all common sense stuff but it is nice to put some numbers to the ideas.