Dodge Van tow vehicle ??

I was thinking the same thing on the engine. Right now it has the original 318 which actually surprised me to no end that such a big vehicle would have a 318...wow

But I have a 440 setup out of a 77 Ramcharger so, it seems pretty natural what to do :)

That's actually what I was going to recommend. The 440. Because when towing, the mileage between a 440 and 360 will not overshadow the 440's torque difference, so do the 440 slam.