I have a 2023 F350 Crew Cab short box with the 7.3 and 3.73 rear end. I tow a 11000-12000 lb 5th wheel and love it. When running on flat ground I can just leave it in 10th gear and it'll run 70 MPH all day long. Hilly terrain I just lock out 9-10 and it'll cruise at 70 in 8th gear at about 2100 RPM with no problem. I get about 9 mpg towing but it tows it effortlessly. Haven't gone to the mtns or anything yet so I can't reference engine braking but plan to next summer. I'd given some thought to the 4.30 rear end but with what I'm towing I don't feel it would be any improvement.