New aluminum heads housing a 37mm intake and 30mm exhaust valves saved weight over the front wheels and dissipated engine heat. The quartet of camshafts received new profiles over the previous year's specs. Twin 57mm bores of the throttle body were fed by a 90mm mass airflow sensor.
The new Cobra's aluminum flywheel was similar to the one found in the '00 R-model, and it worked in synch with an 11-inch single-plate clutch. The only transmission available was a six-speed Tremec T-56 manual hooked to an aluminum driveshaft and 3.55:1 differential gears. Higher-capacity universal joints and half-shafts were chosen to handle the torque increase.
SVT beefed up the Cobra's suspension for the '03, including revised bushings, mounts, and spring rates. The IRS received a new tubular cross-brace, which was designed to stabilize the differential assembly under hard acceleration (drag-racing Cobra owners ran up rear-differential warranty bills). Roll steer was reduced with revised rear-suspension geometry. Coupes and convertibles had different suspension tuning-a first for the Cobra-with hardtop spring rates measuring 600 lb/in front and rear and droptops wearing 500-pounders in front and 470s in the rear. Gas-charged, monotube Bilstein shocks were specified for all four corners; tubular antiroll bars measured 26mm in front and 29mm in back.
Brakes were Brembo 13-inch rotors with PBR dual-piston calipers in front, and 11.65-inch rears with single-piston calipers. The largest tires ever fitted to a factory Mustang-275/40ZR-17 Goodyear Eagle F1s-wrapped around 17x9-inch five-spokes.
The Cobra body wasn't substantially different from the Mustang GT, but SVT made just enough cosmetic changes to give the snake its own identity. Upgrades to the front included round foglamps, an aggressive front fascia with increased airflow to the engine, a lightweight composite hood with functioning cooling scoops, and model-specific windshield wipers with built-in aerodynamic aids for high-speed work. Rocker panels were reshaped with clean vertical surfaces, color-keyed mirrors were specific to the Cobra, sidescoops received horizontal fins that matched the hood treatment, and the composite decklid featured an integrated spoiler with an LED high-mounted stoplight.
The interior gained new bucket seats with Nudo leather trim and Preferred suede inserts. Drivers received six-way power controls, including switches for thigh, lumbar, and side bolsters. A titanium-color gauge face, illuminated by electro-luminescent lighting, included a boost gauge. The shifter knob was wrapped in leather with a brushed-aluminum insert on top, marked with the six-speed shift pattern. The pedals were trimmed in metal.
Despite the record-setting power output and long list of standard creature comforts, such as power windows, air conditioning, a Mach 460 stereo with six-disc CD changer, ABS, tilt steering, and cruise control, the fastest-ever Cobra coupe retailed for a reasonable $34,065. The convertible was a bargain at $38,405.
John Coletti, chief engineer for SVT, referred to the '03 as "a Cobra R with all the comforts and amenities included."
He wasn't kidding. In no time, reports circulated on the Internet of stock Cobras registering at least 400 rwhp on dynamometers all throughout the country. Using a parasitic drag factor of 15 percent, this meant the blown 4.6L was really putting out 460 hp at the crankshaft-70 more than advertised. To put this into perspective, the '03 Cobra was producing nearly twice the output of the '93.