Only 50 units were produced in Lightweight specification, which makes for an exceptionally rare breed. The car pictured in this story’s gallery is one of those rarefied monsters. It started life as a marketing vehicle for the Ford Motor Company in the late sixties, then it was sold to period engine specialist Dave Lyall. Care to guess for how much? One dollar! I'm afraid I'm not joking.But what Dave Lyall purchased for $1 under the agreement for factory-sponsored race cars is now worth $150,000 or thereabout based on the trend set by previous auction results. The car that’s central to this story is slated to cross the block this October at the Mecum Auctions Chicago sale.Because it’s a Cobra Jet, this type of Mustang is motivated by a 428 cubic inch version of the FE V8. Specifically designed to churn out obscene amounts of horsepower and torque, the engine was central to winning a handful of Super Stock accolades. Finished in the Lyall’s trademark racing livery and complete with Cragar SS wheels, this is one seriously wicked machine. Mecum Auctions highlights that this 1968 Ford Mustang Cobra Jet Lightweight is “well documented with copies of the window sticker,” plus Dave Lyall's $1 contract, the Michigan title search, Ford internal memos about the 428 Cobra Jet Lightweight Mustang program, and a Marti report. The seller also offers photographic documentation of the car’s restoration.When you think about it, $150k isn’t a lot of money considering that a Mercedes-Benz S600 luxobarge retails for just about $20,000 more.