Boss 429s are some of the rarest Blue Oval pony cars ever to exist, and this low-production-number example is no exception. Finished in its Royal Maroon hue, this 1969 Boss Nine wears KK no. 1390, which means its a February-built car. It was the 189th example produced, making it an ultra-low production-number model.

According to the original Mecum Auctions (where the car will cross the block next month) listing  it is one of only 279 equipped with the rare 820-S NASCAR solid-lifter engine and smooth chin spoiler. The dark-red Boss 429 features a numbers-matching 429ci V8 filled with the familiar forged pistons and steel crankshaft. As if boasting low-production-numbers wasn’t enough, you can add one of 132 produced with these paint and trim options to its rarity roster.

What’s more is that the factory-installed smog pump is still installed, along with a dual-point distributor, factory exhaust manifolds and a Holley carburetor. The Boss hasn’t been tampered with much either, seeing as the 1969-specific, 3/4-inch rear sway bar and transverse mufflers are still present, only adding to the value of the one-of-a-kind ’Stang.

A unique KKX competition suspension resides under the body of the Boss and handles all of the power being transmitted from the factory four-speed manual transmission and 3.91 Traction-Lok differential. Of course, having power steering and front disc brakes doesn’t hurt either. Make no mistake folks, this Boss is sure to sell for big bucks come April 5-7 at the Mecum Auction in Houston, Texas.

For more information on this Boss, check out the original listing here.