It’s undeniable the impact the Ford Mustang has had on the American automotive market, and this week celebrates the iconic Pony Car’s 50th birthday. Helping commemorate the occasion is this one-off Mustang built by RK Motors based on the 1967 Shelby GT500. We say ‘based on’ because under its factory-fresh appearance lies a host of performance add-ons and go-fast bits that could make a grown man cry. At the ‘Stang’s heart is a hand-built 527-cubic-inch Boss Nine, all-aluminum V-8 cranking out roughly 800 horsepower. It’s backed by a custom-built Tremec T56 six-speed manual transmission that sends power to the pavement through vintage style 18-inch wheels mounted with BF Goodrich G-force sport comp rubber.