My 83' Crew Cab Dually project

[tinydb84]

I ended up using one piece of 3x4x.250 and splitting it in two:

Fit it in the frame:
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I welded the top in first completely (the white paint is weldable primer, I knew I wouldn't get around to painting it for a bit and didn't want to deal with rust after I cleaned everything). Then removed 6 inch sections at a time from the bottom as I welded it in so that way I knew the frame would flex or move too much:


Then I welded in some L shaped fishplates because I am paranoid:

Take the body off if you have the space. That probably was the worst part.

[DblTrbl]

Those fishplates are a good idea. I think I'll steal that from you.

Is there a big risk of warp/flex when burning these in? It seems like the 1/4 wall tube would be pretty resistant to that.

I cant quite see from your pics; where did you end the tube at the front? Are you into the Z'd area? I'd like to tie my 12' tube right into the Z with as few joints as possible...Less joints: less movement.