Porsche couldn’t be much more popular than it is right now. Cars that used to cost $450,000 brand new are selling for nearly $2,000,000 in the used market. Classic examples are seeing a boost, too, and this 1965 356B/912 Prototype should go for around half a million dollars.

That might come as a surprise to some who keep track of the general 912 market. Last year one of the nicest examples ever sold for just under $140,000. It was a one-owner car with an incredible history and many accolades. So why might this car go for more than three times that when the Mecum Kissimmee auction ends on January 16?

That word prototype has a lot to do with it. Porsche built just six prototypes of the 912 with its four-cylinder engine. Of those, just two remain and this is one of them. While not as fast or flashy as the 911, the 912 plays a vital role in the history of Porsche.

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The engine is also original which only sweetens the deal. Instead of just owning a pristine and classic Porsche, the new owner of this car will have a pillar that the brand was built on.

Porsche sent the car to the USA and used it as a development and test vehicle. They also used it to introduce the American dealer network to the 912, with the badge affixed to the rear engine grille that specifically says “1st U.S. PORSCHE DEALER TOUR – STUTTGART- 19-22 – JULY 1965” testifying to it. It doesn’t get much cooler than that.

The car itself is very clearly a prototype. Small details throughout the build make that clear. For instance, the door hinges are aluminum instead of steel and the dash has body-matching paint, unlike production 912 models.

Finally, beyond all of these cool little facets of the car and its history, Porsche itself has authenticated the car. During the 2014 Porsche Parade Concours, this 912 scored 297.4 points out of a possible 300. As far as classics go, this prototype should tick all the right boxes for a Porsche collector, hence Mecum’s $400,000 – $500,000 estimate.