patperry2766 wrote:
Whatever you do, try to find one with the max trailer tow package. They are few and far between, but worth it for a trailer your size. They are generally distinguished by the larger mirrors similar to the 3/4 & 1T ones.
I think the max package would be almost necessary for the trailer that the OP has. Everything I've heard or read about the 3.5 says it will pull your trailer but it won't handle as well as an F250.
I used to have a 24' motorhome with a 460 and it wouldn't pull nearly as good as my current F250 with a 6.2 pulling my camper. The 6.2 gas mileage isn't good but it's quite a bit better than the 460.