To get that high tow rating on an F150, you have to have the HDPP and those are not on the used car lots. You might find a MaxTow equipped one and that's better, in that you get a bit more GVWR on the truck, but forget about towing an RV of that 'tow rating' size..
I have a 13 F150 MaxTow Eco with #7700 GVWR and I'm towing a #7000 loaded TT and that's about all I want to tow comfortably with it. It can tow more, has tons of power, but just for the shear comfort level of towing, it's all I want to tow with it.
You will run out of payload long before you reach any 'tow rating'.. So, choose wisely.. The newer Fords all have the auto engine start/stop feature.. No cylinder deactivation, and you can turn off the start/stop, but have to do that every time you start the truck..
To get the old 6.2l in an F150 you have to get the Raptor or a Platinum or higher trim level probably some 5+ years ago.. But, they don't have any payload left, so won't do you any good anyway..
Good luck! Mitch
