I've got a '92 F600 with 20' box. We're using it to move and I'd like to tow a Fiat 500 behind. It's got a diamond plate C-channel rear bumper / step.

I was wondering if I could just drill out the bumper and pop a 1" shank tow ball on there to accept the car dolly. Height-wise it would work. Just wondering if the C-channel step would be strong enough.

 

Without knowing more about the bumper a qualified no

F600 factory trucks did not come with diamond plate bumpers from the factory... so this is a bumper the box manufacturer probably built,,, if its 1/8 inch ..probably not.. you would need cross braces etc to make it a tow bumper

Why not be safe as it sounds like you dont have the fabrication experience and go to a shop that install tow hitches....

 

How the bumper might be attached to the frame rail and overall rigidity of the bumper unit is what I'd look at. You might also install a tow safety chain to the frame rail if you go ahead still with some concern about it.