What do you consider the most iconic Mustang of all time? For most, its easily the ’69 BOSS 429 Mustang. Built specifically to do battle with Dodge’s legendary HEMI, NASCAR’s rules required at least 500 passenger cars be outfitted with the 429 semi-himi mill, and sold to the general public. So Ford, with the help of Kar Kraft, outfitted only a rare 859 Mustangs with the powerful engine. In just a couple of weeks, one of these legendary rare Stangs will be hitting the Mecum auction block in early October.

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This pristine '69 BOSS 429 still features its complete original drivetrain

This incredible example was once part of the personal collection of MLB All Star pitcher John Smiley and sits today covered in a correct coat of Black Jade paint. Driven only 35,162 miles, the Mustang still carries with it its original 429 powerplant, close ratio 4-speed manual transmission, and its 3.91 Traction-Lok rear-end. In 1969, this trio was the absolute best in Ford performance. Rated conservatively at 375hp, much debate has been made to what they actually left the factory with. Some claim that the engine made as high as 600hp.

The Boss 429 treatment also included factory power steering, front power disc brakes, 3/4 inch rear sway bar, and chrome Magnum 500 wheels. Not only is this Boss listed in the 429 registry, it also comes equipped with an extensive Marti Report.

The legit ’69 Boss 429 Mustang will go up for sale at Mecum’s Chicago 2014 on October 9-11. Recent auction results have been seeing legit examples like this sell in the $300k – $400k range.

Now we leave it up to you, what do you think this incredible example will bring?