Hello fellow Iowans!

Question about my 77 F250 -

When standing behind the truck and looking at the rear wheels, I swear the tops of the tires tip "IN"...kinda like a vehicle would if it had independent suspension and was loaded. Maybe this is an illusion..maybe I am crazy but it bugs the heck out of me. The tires are wearing goofy too, in the inside edge...but then again, these tires were used when I put them on and I put the best two in the front so if they are cut a bit it could be from the previous vehicle. I plan on marking them with some chalk or spray paint and running them to see where the wear pattern is. But back to the point of them tipping....I believe the rear end is a Dana 60 4:10, which is geared way too low for what I need so replacing the whole thing would't hurt my feelings a bit if I could find another with different gears. Is what I am seeing possible? I have jacked the truck up and tried to see if there was any play in the axles/bearings..etc...I found none but I really don't know what I am looking for. I see no leaking and to my knowledge this axle had been rebuilt 5-6k miles ago. Can the entire axle housing bend?? ANyone have a similar rear axle with different gears for better fuel mileage?!

FYI....this is a 1977 F250 crew cab w/460