These frame boxing sets are designed to reinforce your failure prone factory frame.  This kit works in conjunction with our Cummins motor mount kit and cross member.  The standard kit boxes the frame rails in from the steering box to past the transmission crossmember, while the extended length option does the entire frame for the ultimate in strength and flexibility. Fabrication and welding are required!  You must replace the factory front cross member when using our Cummins conversion motor mounting kit. Say goodbye to frame issues and cracks, it also comes with machined DOM sleeves and grade 8 hardware for the steering box to reinforce that trouble prone area.  Made in the USA!