How do you make a rare care rarer? Apparently, you add an R on to the end of it. Actually, the 1965 Shelby GT 350 R is one of just 36 ever built and 25 GT350 R’s still remaining. It’s one of the priciest American cars, new or old, and as you can imagine these cars don’t change hands very often.

In fact, it is so expensive and rare that it is being auctioned off by Gooding and Company, an auction house that deals in very high-end, classic European exotics. It is a company more accustomed to selling Porsches than Mustangs.

Yet this mythical Mustang is in good company, as it is a tried and true racer. It has an enviable racing history, including a SCCA Production Class-B championship with Freddy van Bruen at the wheel. It will share the auction block with one of about 108 Porsche 904, the first racing Porsche to feature a fiberglass body and a well-versed racer in various SCCA events.

The 1965 GT350 R was a special kind of race car, sharing the K-code 271-rated (but really about 350) horsepower 289 engine. It also got dual electric fuel pumps, an aluminum case Borg-Warner T-10 transmission, special oil pan baffling and valve cover breathers and bucket seats while ditching heaters, defrosters, or radios. They were pure race cars designed to compete against the Corvette, and compete they did. In 1965, GT350 R’s won five of six SCCA divisions.

This particular car was last sold in 2006, and is up for auction again. It is expect to fetch between $650,000 and $850,000 at the Scotsdale auction January 21-22, and hopefully it will live out its days in a climate controlled private collection, with regular oil changes and dustings. Not a bad retirement plan for an old racer.