The real stuff:
The 1965 Shelby R-model !!
How did Ford got that sporty image for the Mustang ? They asked veteran Carroll Shelby to give them a hand. Who was better qualified than him ? The street model was pretty to close to a full blown race car, but find here the details on how  Dr Shelby made 36 cars into high performing and winning beasts !
Before you can actually make a race car and drive it, you have to fullfill a couple of rules. Ford wanted the Mustang to run in the SCCA (Sports Car Club of America) and they asked for at least 100 produced 2 seater cars. Based on those 100 limited production cars, the racing version could have either a modified engine or a modified suspension. Ford initially failed to convince the SCCA, but Shelby had a word with John Bishop, the executive director and Ford received the green light.
Step one was to turn a Mustang fastback into a production sports car, the "street" Shelby GT 350 with its essentially unmodified and Ford-warranted 289ci HiPo engine and its highly modified Shelby American-designed suspension.
Step two was to build 100 of the cars, a few for racing but the majority for the dealer showrooms.
Step three called for the creation of a race car in compliance with the SCCA's edict regarding the modification of either engine or suspension, since the suspension was allready optimized, Shelby American could internally modify the race car engines
After a couple of weeks into production, the SCCA found 100 white fastbacks with blue stripe schemes in the Shelby American plant ! Thanks to that the "Cobra-Mustang" was approved for B/production in 1965.
The GT350 entered the race-tracks and started winning thanks to both Cobra team veterans and regional independents.
The building
If the "street" models allready missed some parts, then check out the R-model: they were built with the goal of eliminating excess weight !
Many things were deleted: steel hoods, hood latches, grille bars, mustang badges, rear seats, radios, exhaust system, sound deadener, seam sealer and undercoating, window regulators, side glass, backlight, gas tank, door panels, headliner, heater/defroster system and carpet. The front bumber was replaced by a lightweight fiberglass apron, ducted for brake and engine cooling and the rear bumber was simply removed ! Even the side pillar extractors were removed and a thin aluminum plate was riveted over it. The missing glass was replaced by pull-up Plexiglas side windows  in aluminum frames in the doors and a molded Plexiglas rear window replaced the heavy original one. Nearly 500lb was eliminated ! (250kg)
The HIPO engines were removed and dismantled at Shelby American. The heads were ported and polished, internal components were balanced and reassembly was done to blueprint specifications. Each engine received a camshaft for top end power, a fully degreed harmonic balancer and a 7qt Aviad oil pan which required a custom-made anti-sway bar. Shelby also modified the oiling system and installed an oversized radiator; an oil cooler was added as well. Under the 715cfm center-pivot Holley carb there was a dual-plane high-rise aluminum intake manifold. Also installed were large tube headers, a Stewart-Warner electric fuel pump and a straight pipe exhaust system. The dynomometer registred 350BHP !!
To deal with the realities of racing, the R-Model also received slightly flared and re-radiused wheel openings, 34gal baffled gas tanks (actually two stock mustang tanks welded together), quick-release gas caps fitted with splash collars, gutted dash panels equipped with six CS analog gauges, two lightweight and snug racing seats, 3in competition harnesses and a four-point rollcage for both rigidity and driver safety
Allthough there was similarity to the "street" model with the Le Mans stripes and the lower body stripe, the R-Models looked a lot meaner thanks to the Goodyear Blue Streak tires mounted on American Racing five-spoke magnesium wheels, and the front valance . Each R-Model was tested by Shelby American at Willow Springs
36 R-Models were made, their price ranged from $6,500 to $7,150. Most of them were sold in the US but a couple went to Europe and several to Peru !
In 1967 the Belgian Shelby dealer Claude Dubois entered the Le Mans race with this GT350, the Shelby ran well untill the gearbox broke down....


Here are some pics I took at the 40th Anniversary Meeting in Nashville in April 2004. I sat high in the tribune to follow the race and went to the pits afterwards to take some pictures of the Shelbys. I was nice to see them upclose and even nicer to see and hear them race, the reason why Carroll Shelby created them.... Enjoy.