Why would towing be different in a newer vehicle vs my 14 year old van?
Power. A newer vehicle will have significantly more HP and torque, as well as a better transmission. I think you will be surprised, and not in a good way, when you get to the scales with your conversion van. As mentioned earlier, I used to tow with a conversion, and that nice interior, with it's extra carpet, soundproofing, amenities, and comfy seats, weighs a lot more than what the factory would install in a standard passenger van. A good amount of payload is already gone, especially if it's a 1500 series.