Karl---I have a friend that has a 4.7 in his Dodge. He tows about 7000lbs. He gets 8 or less towing.
I have an 01 5.9 gas. It does what I want it to do. When I purchased it over 5yrs ago it was great. Diesels have become much more popular, and I have towed with them. It is a night and day...