Only rated at 24,000 pounds? That's total BS!
I've pulled 15,000 with a 1/2 ton Chevy that had the 4.7 in it. Pulled it very well, stopping however was a total different subject.
I've towed 20K with my Chevy Duramax 2500 and it was like nothing was behind me. I'm more then sure that 450 can pull 50.