1971 AC 428

In the mid-1960s, AC Cars began transforming its Cobra sports car into a luxury Grand Tourer, displaying a two-seater convertible at the 1965 Earls Court Motor Show and a fastback-styled Coupe at the Geneva Salon a year later. Production of the AC 428 Frua lasted from 1967 to 1973 with just 81 examples built, comprised of 30 convertibles and 51 fastbacks.

The Cobra MKIII coil-sprung, fully independent suspension was extended by 6 inches in the wheels and clothed with elegant steel coachwork by Pietro Frua, with a similar design to Maserati's Mistral. The boot lid and bonnets were fabricated from lightweight aluminum. The chassis was built at the AC plant in England and then shipped to Italy where Frua fitted the body before sending them back to England to have the powertrain and trim added. The chassis was rather conventional with rectangular and square tubing connecting the steel body to the frame. Its wheelbase measured 95 inches, its length of 176 inches, and its width of 68 inches.

The model was named in reference to its 428 cubic-inch (7-liter) Ford Galaxie FE engine which produced less power than the Cobra 427's. Nonetheless, with 345 horsepower on tap and an overall weight of 1,416 kg, the AC 428 was capable of sub-six-second 0-60mph times and 0-100mph times of around 14.5 seconds, with a maximum speed in excess of 140mph. The majority of the cars were equipped with automatic transmissions, which complemented the grand touring persona.

The 428 cubic-inch V8 engine produced 345 horsepower at 4,600 RPM and 475 lb-ft of torque at 2,800 RPM. It had 10.5:1 compression, hydraulic valve lifters, and either Autolite or Holley four-barrel carburetors. Some examples received the higher performance cross-bolted main Ford 427 engine which produced 385 horsepower at 5,600 RPM and 460 lb/ft of torque. Transmission options included a fully synchronized four-speed close-ratio Ford Toploader unit or a three-speed Ford C6 automatic. Steering was by a Rack & Pinion and the differential was a Salisbury unit with a 2.88 drive ratio for automatics and 3.08 for manuals. Four-wheel power-assisted disc brakes provided the stopping, with Girling 3-pistons, and dual remote servo assistance. A fully adjustable independent suspension setup with double triangular wishbones, coil springs, and hydraulic telescopic shock absorbers was located at the front and rear.

The AC 428 Frua was stylish, elegant, and luxurious with performance that rivaled the supercar elite of the day. Its Achilles Heel was the steep price which was roughly twice that of a Jaguar E-Type and more than an Aston martin DB6.

by Daniel Vaughan | Oct 2021