It'll start the truck alone. I know, I was surprised too.When you say two 7.4 batteries will START your truck "no problem", are you saying they will start your truck ALONE, or are you just using them to give your regular battery a quick boost? Because those two small batteries would have to produce some 400 cold cranking amps of power during the time you are cranking your engine.
As far as the tongue box, I can't believe it weighs 46 pounds. I have one and I swear it didn't seem that heavy, but I'm sure the specs are close.