The 1965-67 Shelby GT350 was not built for comfort or ease of driving. There were 34 "GT350R" race-spec cars built specifically for competition use under SCCA rules, and the model was the B-Production champion for three straight years.

Wimbledon White with blue stripes, the Shelby GT350 R was a purpose built racecar that became the template for GT350 road cars to follow. Racing in the SCCA’s B/Production class, Shelby was Ford’s answer to winning the Road Racing Championship for several years. The cars were built in series as a turnkey racecar.

Prepared in conjunction with Ford, stripped out 271 hp Mustangs left the factory for conversion in Shelby’s facility. The first arrived without side or rear windows, heaters, defrosters, upholstery, headliners, insulation or sound deadening.

Many changes were done to the body, including the fittament of a distinctive front apron in fiberglass. Flares were added to the fenders to accommodate 15×7 inch wheels. Furthermore the side and rear windows were were replaced by Plexiglas with aluminum frames.
Underneath, Shelby changed the pickup points on the suspension, added traction bars for the rear suspension and installed a new differential.
Inside, a new instrument cluster was added with a tachometer and oil pressure gauge. A large 4-point roll cage was installed with a 34 gallon fuel tank.

The Mustang's suspension was tweaked with the addition of Koni shock absorbers, while larger brakes and a beefier rear-end were also fitted. Shelby started with the 'High-Performance' or 'HiPo' version of the 4.7-litre V8, which produced 271 bhp in stock trim. It was fitted with a large, four-barrel Holley carburettor and produced 306 bhp in street legal trim. The 'R' competition cars used a blue-printed version of the familiar V8, which was good for between 340 - 360 bhp. It was mated to a sturdy Borg Warner T-10 four-speed gearbox.

Official Shelby American test-driver Ken Miles debuted the GT350 R on February 14th in 1965, fittingly at Green Valley Raceway in Texas. Placing second overall, Miles won the B Production class straight at the Shelby Mustang's first attempt. As it turned out, this was just the start of a hugely successful season, which ended with the GT350 as the championship winning car in five of the six SCCA divisions. Among the many famous racers scoring successes behind the wheel of the GT350 were the likes of Jerry Titus, Mark Donohue and Pedro Rodriguez.