Im wondering the best way to add to the length of the frame rails and do it safely. I have no issue in the fab area and know that this can be done. Im just wondering the safe way to do it and how much you can add.

HI Well JUST a suggestion..OK.. Soimething to think about. Need to start with a strong frame so you can load it up. Why not start with a used commerical boat trailer($5000)..?? 50 ft. long,low, wide, and build a box on the frame. Make what you want. OR 53 ft used dubble drop moving van($7000) and lower the roof to about to 11-12 ft. All this on a fifth wheel frame that will hold you and the dulley. Put a Volvo, 400-500 HP and lets go to town. JUST a thought....