I am restoring a 54 f100 short box however it does not have a bed. I know of a step side bed from a '77 f150 for sale. Will that mount on my '54 with little or no modification?

 

To my knowledge the only problem you'll have is that you'll have to redrill the holes where the running boards attach to the fenders.

 

The '73 and later beds will need to have fenders repositioned as Stephen 67 says. Although with the wheel tubs in these newer beds I,m not sure if you can reposition them. The beds look similar but the tops of the beds rails are flat and the tailgate and front are wider. Also there are wheel tubs and the gas filler exits through the left fender. And the rear sill is different too.