The first Gen Duramax, which is quite a bit more powerful than the 7.3 Powerstroke, only put down ~200 hp/ ~400 tq at the wheels. Like you said, the 7.3 gas puts around ~360 hp/ ~410 tq. Combine that with the 10 speed auto, the 7.3 gas will out tow all those early diesels, up to and including most 6.0 Powerstrokes. The F350 7.3 gas with 4.30 gears is rated up to 20,200 5th wheel/gooseneck in a Crew Cab 4x4.
I've owned a 7.3 Powerstroke, and currently a 7.3 gas. my new gas truck will out tow my old diesel easily, and much more comfortably also.
