Rob Bonney Fabrication 73-91 Suburban frame boxing set, designed to be used in conjunction with our Cummins Motor mounting Kits. This kit goes from the steering box to the rear spring hanger. Plates are cut and formed from 1/8" cold roll steel, and includes machined dom sleeves and gr. 8 hardware for the steering box. Welding and fabrication REQUIRED! Factory front crossmember will need to be replaced with rectangular tubing. Designed to work with our 73-87 Cummins 6BT motor mounting kit. Made in the USA!