The Mustang was Ford’s biggest commercial success since the golden days of Model T production. Originally conceptualised as a strict two seater, FoMoCo senior executive, Lee Iacocca, realised that its success hinged on volume sales. And volume sales were exactly what Iacocca got, over 22,000 Mustang’s being sold within the first day and more than 100,000 rolling off the production line inside four months. Within two years, more than a million would be sold, but come summer 1964, Ford’s executives thought the bubble was about to burst.
All GT350’s started life on the Ford production line as Wimbleton White K-Code DSO fastbacks with 271bhp 289 V8’s and standard black interiors. DSO referred to the unique blend of upgrades these cars were built with, several special bits from the Ford parts bin being added before despatch to Shelby. The front disc brakes were kept, but sintered metallic pads were used instead of the softer stock ones, station wagon drum brakes with larger metallic-lined shoes being added at the back. There were also nine-inch Detroit Locker differentials, under-hood ’Export’ bracing and close ratio T-10 Borg Warner four-speeds, these much ligher transmissions being fitted with an aluminum case to save weight.
Cars were shipped from Ford’s San Jose plant to Shelby American’s Los Angeles facility without hoods, grilles, rear seats, exhaust systems or emblems. Then the transformation really began. The SCCA’s B Production rules said that qualifying cars could run either modified suspension or engines, but not both. Shelby opted for the modified engines route and thus suspension was created from existing Ford components. The front-suspension mounting points were re-positioned and the A-arms lowered (reducing ride-height at the front by an inch).
The live rear axle was held in place with a semi-elliptical leaf spring and stronger torque reaction arms on top of the axle itself. Adjustable Koni shocks were installed all round whilst there were also rear traction bars and thicker anti-roll bars. Shelby further enhanced the GT350 with a quick-ratio steering rack and oil coolers for the differential, the stock Mustang radiator being replaced with a much bigger one from the air-conditioned Galaxy 500. Finally, the battery was initially repositioned from under the hood to the trunk, but after owners began complaining about unpleasent fumes and corrosion, Shelby reverted back to the original location. Two 15-inch wheel styles were available, white-painted steel items or cast magnesium Crager rims, these having originally been shod with Goodyear Blue Dot tyres. Engines were based on Ford’s new Hi-Po 289, this small block V8 already producing a respectable 271bhp direct from the Detroit factory. Once on Shelby’s production line, each motor was equipped with a new aluminum Cobra hi-rise intake manifold to replace the stock cast-iron item. A Holley four-barrell 715-cfm carburettor was designed not to starve or flood during hard cornering.
There were lightweight tubular Tri-Y exhaust headers that fed straight-through pipes and low restriction glass-pack mufflers, the exhausts being re-routed to exit just ahead of the rear wheelarches. Engines were dressed with a chrome air cleaner, finned aluminum Cobra rocker covers and a cast alloy oil pan. This amounted to 306bhp at 6000rpm, enough for a 138mph top speed and 0-60 in 6.6 seconds. Externally the GT350 could be identified by its hood-mounted air scoop, the front lid having been made from glassfibre and held in place with fastening pins.
The man who had conceived and mid-wifed the Cobra got another call from Ford, applied his Texas charm to SCCA’s executives and decision makers, and came up with a plan to build a Mustang-based sports car. A hundred had to be ready to go by January 1, 1965 and they were, lined up and resplendent in their uniform: Wimbledon White livery with Guardsmand Blue stripes, fiberglass hoods and Shelby identification, ready for the SCCA inspectors’ perusal. They weren’t quite ’done,’ but they passed muster.
Under the white paint and graphics the Shelby Mustang had beefed up suspension with lowered front A-arms, rear axle trailing arms, Koni shocks, bigger brakes, quick steering adapters, strong front spring tower supports and a Detroit ’No-Spin’ locking differential in 9’ Fairlane station wagon rear axles. They all had aluminum case Borg-Warner T-10 four-speed gearboxes and K-code engines modified with Holley 715cfm 4-barrel carbs on high-rise intake manifolds, aluminum oil pans and fabricated tube headers feeding dual exhausts with glass pack mufflers. The rear seats were replaced by a fiberglass package shelf, leaving only the front seats. That made it a ’sports car,’ at least to the SCCA.
The Shelby GT 350 was a modest success, with 562 built in 1965 of which 36 where ’R’ models built by Shelby specifically for racing. The first 252 ’66 Shelby Mustangs were actually built by Ford at the end of the 1965 model year and brought to ’66 specifications by Shelby. Wisely the successful ’65 GT 350 wasn’t changed much. No sense messing up a good thing. With a little more time to prepare, Shelby’s designer Peter Brock came up with some distinctive, and functional, external modifications including cutting out the C-pillar sail panel and installing triangular windows and adding functional air intake scoops to help cool the rear brakes. Four new colors were added and most ’66 Shelbys used Mustang’s optional fold-down rear seat to comply with the letter, if not the spirit, of SCCA’s two-seater rule. Automatic transmissions were added as an option, as was the formerly-standard and noisy limited slip differential.
The distinctive identification of the 1966’s and more user-friendly option availability boosted the GT 350’s success with 2,378 built. The GT 350’s reputation far exceeds the total number built as they are among the most appreciated of all American collector cars.