The 1965–1966 cars were the smallest and lightest of the GT 350 models. These cars are often called "Cobras", which was the Ford-powered AC-based two-seat sports car also produced by Shelby American during the same period. Both models use the Cobra emblem, similar paint scheme, and the optional "Cobra" valve covers on many GT350s that were part of a marketing tie-in by Shelby, as well as one of his iconic symbols. All 1965–66 cars had the Windsor 289 cu in (4. 7 L) HiPo K-Code 271 hp (202 kW; 275 PS) V8 engine, modified with a large 4-barrel Holley 715 CFM carburetor to produce 306 bhp (310 PS; 228 kW) at 6,000 rpm and 329 lb⋅ft (446 N⋅m) at 4,200 rpm of torque. Marketing literature referred to this engine as the "Cobra hi-riser" due to its high-riser intake manifold. Beginning as a stock Mustang with a 4-speed manual transmission and 9" live rear axle, the cars were shipped to Shelby American, where they received the high-riser manifolds, Tri-Y headers, and were given larger Ford Galaxie rear drum brakes with metallic-linings and Kelsey-Hayes front disc brakes.