The early 70's models used two 1-87-1 3501522 Torque Screws, on on each side; they are listed in the 70-71, 72 & 73 parts manuals. The head was designed to snap off after installation. They're a real PITA to remove.







The torque screws aren't listed in the 74 parts manual. At some point during these years the method for theft deterrent changed to the bracket and rivet design reflected in the previous posts.