Two very important ratings not in the specifications is GCWR=Gross Combined Weight Rating. This is the maximum both truck and trailer combined weigh. The second is towing capacity, which is dependent on gearing, engine output, transmission, and engine cooling capacity.
Those ratings will be found in the owners manual.
This is just my observation- That E150 spec sheet,if I read it correctly, is the very first 1/2T rated vehicle with LR "E" tires as OEM, and is a very good thing, if it is accurate. IMO if that van has "P" rated tires it will not be a pleasant towing experience.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert theConstitution. "Abraham Lincoln"