I like the Fords for towing. I just bought two Class A RVs - the first had a Chevy 454 carb motor - drove it around and thought it could pull an open trailer - tested it out loaded and I know the trans would die - only a three speed. Selling that RV before I kill it towing.
Bought a second RV with the Ford 460 EFI and a Banks system with the trans commander. What a difference - this will pull an open trailer without too much heartburn. A big point is having the Banks Trans commander - that will save the tranny. I plan on installing a temp sensor just to be sure I don't melt anything.
I also tow with a 2003 Ford F350 V10. That pulled my 26 foot enclosed no problem. The trailer weighed about 9,000 loaded. Put it in cruise and it would drop to third on the steeper grades - always got about 8 mpg towing, 10 mpg unloaded.