A beloved feature of the early Ford Mustangs were their long options lists and while most prospective customers chose from pedestrian items, such as two-speed wipers and stereo radios, performance-minded buyers chose the “K-code” high-performance V-8 option. At $433.55, the “Hi-Po” V-8 was the most expensive option available, but these discerning buyers received their money’s worth. So named for the “K” designation in their chassis and engine numbers, these special Mustangs featured a 289 cubic-inch engine with solid lifters over four-inch cylinder bores and heavy-duty connecting rods, high-strength, flat-top pistons, and a high-nodular, cast-iron crankshaft. Each cylinder head wore enlarged intake and exhaust valves, while cast-iron, header-type manifolds helped the machine breathe through a standard dual exhaust system. Meanwhile, the chassis was upgraded with the Special Handling Group, which included heavy-duty shocks and springs, and a front sway bar.

Ford advertised the K-code as, “designed especially for the true sports enthusiast, this powerful V-8 provides sports car performance with breathtaking acceleration to match the Mustang's sports car styling.” Upon its debut, the spirited K-code engine further solidified the Mustang’s capabilities as a serious performance machine in an era when Ford Motor Company was dominating all aspects of auto racing.

Finished in factory-correct Raven Black over a Pony Deluxe Black Crinkle Vinyl interior, one of these coveted high-performance Mustangs is offered for sale here. Per a report by the official K-Code Registry, this example is the sole known 1966 K-code Mustang Fastback to be finished in all black and equipped with both the GT Equipment Group and Pony Deluxe interior packages. The car is reported to have received a recent nut-and-bolt restoration to exacting standards and is importantly still powered by its numbers-matching K-code 289 cubic-inch high-performance V-8 engine.

This numbers-matching K-code Mustang represents a truly wonderful opportunity for collectors of American performance to acquire a nicely equipped, uniquely finished fastback.