feets I am planning a 518OD and thinking 3:55 gear

Paul I thought the unsafe 15 passanger maxi van were the next generation 1993 up as they sit pretty high up like a 4x4. Mine sit way lower. I was figuring not overloaded and weight distributing hitch with sway control would be ok with not going over the speed limit 60 MPH and leaving plenty of room in front.

65Fury440 the B250 is rated as a 3/4 ton and owners manual states 5,000 with 318 & 7000 with the 360 with towing package and 3.2 or 3.5 axle ratio
I would have preferred an 8 lug suspension for the better brakes but the specs above from the manual say it it adequate.