Documenting a Ford test car

After getting the Mustang home, Isaksen knew that he’d made the discovery and purchase of a lifetime. Once he started researching the car and breaking down its VIN, the rarity of the ’69 Mustang GT hardtop started to become much clearer. According to the 428 Cobra Jet Registry, for the 1969 model year, Ford produced a mere 86 GT hardtop coupes with the R-code 428 CJ and four-speed transmission. He also learned the district sales office (DSO) code of “89” in the car’s VIN represented “Transportation Services,” indicating that the car was ordered for Ford use, perhaps for testing or as part of an in-house fleet.
This 428 Cobra Jet engine is equipped with Ram Air, and is good for 335 bhp at 5,200 rpm and 440 lb.-ft. of torque at 3,400 rpm.

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A hint of what lurks under the hood... R-code (Ram Air)

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Fortunately for Isaksen, Lois Eminger, a Ford employee who sold copies of original Ford invoices for many years, provided copies of the hardtop’s factory invoices, so Isaksen quickly learned that his GT hardtop had originally been sold to Ford Division Product Engineering on Sept. 20, 1968, for delivery to the I.R. Building Garage in Dearborn, Mich. The invoices also confirmed the car’s original options: GT Equipment Group; 3.25:1 Traction-Lok differential; F70x14 white-letter tires; Wimbledon White paint with red Interior Décor Group; AM Radio; front head restraints (headrests); power steering and brakes; and Power Ventilation.