From my experience you will need 1 1/2" - 2" tire clearance to the bed sides or the tires will rub the bed sides. I got a '79 Camaro rear axle in my '49 Chevy 1/2 ton. I tubbed the bed with "Mini" tubs for the added tire clearance. The tubs are 1 1/2" , so now I have 2" clearance from inside of tire to bed side. Ford used a set up like this from the factory or late '40's early '50's 1 ton pick up beds. I use no rear sway bar because it made the ride to stiff.
