1971 AC 428 Convertible
|Also called||AC 427 |
|Body and chassis|
|Engine||7 litre V8|
3 speed automatic
|Wheelbase||95 in (2,413 mm)|
|Length||176 in (4,470 mm)|
|Width||68 in (1,727 mm)|
|Height||49 in (1,245 mm)|
|Curb weight||3,150 lb (1,430 kg)|
The AC Frua or AC 428 is a British GT built by AC Cars from 1965 to 1973. With an Italian body, British chassis, and American big block V8 it is a true hybrid. Production was 81 cars built in total: 49 coupés (known as fastbacks), 29 convertibles, and 3 special bodied.
The Frua is built on an AC Cobra 427 Mark III chassis extended by 6 inches (150 mm). Chassis were built at the AC plant in England then shipped to Frua's workshop in Italy where the body was fitted and then sent back to England to have the power train and trim added. The cost was high and the cars could not be sold at a competitive price. Unlike similar cars such as the Iso Grifo, Iso Rivolta, Monteverdi, and De Tomaso models of the period, the AC Frua features fully independent racing based coil spring suspension.
The AC Frua was never fully developed because AC Cars lacked the financial means. The car's main drawback is a tendency of the V8's heat to bleed into the cabin.
Chassis construction was similar to most Italian supercars of that era, with square and rectangular tubing connecting the steel body to the frame. Though the 4-inch (100 mm) tubular chassis allowed both coupé and convertible versions to be rigid, the design was intricate and prone to rust. The bonnets and boot lids were fabricated from aluminum.
The AC Frua competed with Ferrari, Lamborghini, and Maserati models. Built over a stretched AC Cobra 427 chassis, the car had immense performance; the big-block Ford FE engine had larger capacity, more torque and more power than similar Italian cars, but in a car of similar weight.
John Mclellan said in his book "Classic ACs, Auto Carrier to Cobra" that Derek Hurlock once said to journalist Mike Tailor: "I like the 428 because it fits my image of a true GT Car". He is quoted in Autocar "Like anything exclusive, especially from craftsmen, it costs a lot of money. For this you get one of the fastest cars on the road, guaranteed to make an impression anywhere, and backed by a small company that cares. This one AC that joined that select company of very fast, very luxurious touring automobiles which moved effortlessly from current model to collector's piece". The magazine published a road test report in 1968 of a 428 coupé, and recorded a maximum speed of 141 mph (227 km/h) along with a 0 - 60 mph (97 km/h) time of 6.2 seconds. The acceleration time was fractionally better than the magazine's testers had achieved with an Aston Martin DB6, but the Aston Martin was comfortably ahead on top speed. The AC's overall fuel consumption for the test came in at 15.6 mpg (18.1 l/100 km), roughly 15% better than the heavy Aston Martin. The AC 428 coupé sported a recommended UK retail price of £5,573 (including automatic transmission), to the manual transmission Aston Martin DB6's £4,460 - itself roughly twice that of a 4.2 litre Jaguar E-Type roadster at £2,225.
Towards the end of the production run a couple of prototypes for an extended range were produced. There was a four-door version of the coupe and a more streamlined version of the convertible that included electrically operated "pop-up" headlamps. Neither were developed due to the precarious state of the company finances.
|AC Frua Technical Data|
|Chassis||"AC Cobra 427 Mark III" four inch (100 mm) tube frame extended by 6 inches (150 mm). Front engine, rear drive.|
|Engine||Iron "big block" Ford FE 428, some models fitted with higher performance cross bolted main Ford 427 engine (side oiler). Hydraulic lifter, Autolite or Holley four barrel carburetor. (Specifications can vary substantially with each car).|
|Bore & stroke||104.9 X 101.2 mm, 10, 5:1 compression.|
|Capacity||428: 7,016 cc (428.1 cu in), 427: 6,997 cc (427.0 cu in).|
|Power||428: 345 hp (257 kW) @ 4,600 rpm, 427: 385 hp (287 kW) @ 5600 rpm|
|Torque||428: 642 N⋅m (474 ft⋅lbf) @ 2,800 rpm, 427: 624 N⋅m (460 ft⋅lbf) @ 3200 rpm|
|Transmission||Fully synchronized 4-speed Ford Toploader transmission (close-ratio) or 3 speed automatic Ford C6 transmission.|
|Steering||Rack & Pinion.|
|Front suspension||Fully adjustable independent suspension with double triangular wishbones, coil spring hydraulic telescopic shock absorbers.|
|Rear suspension||Adjustable independent suspension with double triangular wishbones, coil spring hydraulic telescopic shock absorbers.|
|Differential||Salisbury, limited slip. Ratio: Automatic 2.88, Manual 3.08.|
|Brakes||Four discs power assisted "Girling" 3 pistons, dual remote servo assistance.|
|Body||Coach-built steel body over extruded rectangular and square tubing.|
|Measurements||4,470 mm (176.0 in) X 1,727 mm (68.0 in) X 1,245 mm (49.0 in); Wheelbase 2,413 mm (95.0 in).|
|Unloaded weight||1,430 kg (3,153 lb)|
|Maximum speed||Manual Transmission: More than 245 km/h (152.2 mph), 0 to 100 km/h (0-62 mph): 5.4 s (Autosport Magazine); Automatic Transmission: 220 km/h (136.7 mph), 0 to 100 km/h (0-62 mph) 5.7 s.|
|Fuel consumption||17.2 L/100 km (16.4 mpg‑imp; 13.7 mpg‑US)|
|Production life||1965 to 1973|
|Number of cars built||49 coupes (31 of which had right-hand drive), 29 convertibles and 3 special bodied cars.|
- AC 427, www.motorbase.com Archived 12 November 2014 at the Wayback Machine. Retrieved on 12 November 2014
- "Motor Show Review 1972 on 1973 Cars". Daily Mail. London. October 1972. p. 6 (AC 428).
- "Autocar Road Test A.C. 428 fastback: All-independent Cobra chassis with Ford 7-litre V8 and Frua body". Autocar. 129 (3777): 11–16. 4 July 1968.
Extremely fast and not too heavy on fuel. Plenty of adhesion; little roll, no dive or squat. Firm ride, comfortable seats. Positive steering, too much kick-back. High price for hand-built exclusive GT from small manufacturer.
- http://hexagonclassics.com/cars/ac-428-frua-coupe-automatic-1971/ Hexagon Classics 1971 AC 428 Frua Coupé
- Gunnell, John; Collin, Tom (2004). Standard Guide to British Sports Cars. Krause Publications. p. 13. ISBN 9780873497572.
|Wikimedia Commons has media related to AC vehicles.|
- AC 428 history
- Pietro Frua
- Sales brochure of the AC 428 from 1967
- AC Cars at Curlie
- Information and reviews for the 1960 AC 428
AC Cars road vehicle timeline, 1950–1984