V8 (Weber Carb)
V8 (Weber Carb)

V8 (Weber Carb)

(1973 - 1978)

Weber Carburettors, formally known by the AMOC as the Series 3

The Bosch fuel injected engine of the DBS V8 and early AM V8 was proving difficult to be made to comply with the US emission control regulations, so the decision was made to convert the V8 to carburettors. This may appear odd as now-a-days, it is accepted that fuel injection is the solution to clean emissions. But the reality was that AML never quite got the hang of the Bosch system at the time and the switch to carburettors was a better medium term option. Of course the change actually lasted until 1986 when an electronic fuel injection system was finally introduced to the V8 range.

V8 (Weber Carb)

Externally the Weber carburettor V8 featured a noticeably larger air intake and bulge extending to back of the bonnet to cover the four twin choke 42 mm Webers and airbox. Another change to the body which allows for easy identification of these cars and beyond is the panel below the rear screen. Previously this panel had louvers but these were deleated and the panel  and gained a small lip just above the boot lid. There were many other detailed improvements to the car with revised front seats, revised switches, improved cooling to engine and transmission plus a new fuel tank which gave more luggage space.

Initially performance was still very impressive from the 310 bhp 5.3 litre engine. The automatic car could top 146 mph and hit 0 to 60 mph in 6.2 seconds (Autocar, Sept 1973). The manual was even quicker at 155 mph and 5.7 seconds (Motor, Sept 1973). Although as emission regulations became tighter, peak power output fell to around 280bhp and performance suffered. Thus in January 1977, the engine was modified to ‘Stage 1’ tune with new camshafts, and an exhaust system developed for the V8 Vantage. Just occasionally, these cars are referred to as V8 ‘S’. This went someway to restoring the power output to a more respectable 304bhp.

The GKN alloy wheels on the V8 are of two basic types. The earlier type, with a ridge around the circumference takes tubed tyres whereas the later type has a smooth rim.

The interior picture below illustrates the cockpit of a 1973 V8 photographed during Coys Auction at Silverstone, 1998. It features a traditional combination of stone Connolly Hide and Wilton carpets. Note the lack of walnut veneer – wood in an Aston Martin is a relatively new phenomenon seen on a small number of late Weber carb V8’s and on most cars since the ‘Oscar India’ V8 upto the end of DB7 production.

The gallery below shows a very rare 1974 North American spec AM V8 complete with period 5 mph impact bumpers. Many cars built like this have, perhaps sensibly, been converted to the lighter weight and more aesthetically pleasing European chrome bumpers. Not this car (yet) which has spent all of it’s life in Canada. Delivered very late in 1974, it was one of, if not the last AM V8 delivered in North America prior to the factory stopping production.

Production of the V8 was interrupted for over a year between December 1974 and Spring 1976, when the company hit financial difficulties. In total, 967 examples were produced until the much improved Oscar India was introduced in October 1978. These are the most numerous of all the AM V8 ‘series’ with many more examples than previously built for export with left hand drive.

Identification points of  the AM V8 with Weber carburettor (AMOC series 3)

Identification points of a later example of the AM V8 with Weber carburettor (AMOC series 3)

  • Body/Coachwork:
    • 2 door 2+2 coupe
    • Steel platform chassis with handcrafted aluminium alloy body panels
    • Dual 7” quartz-halogen headlamps
  • Interior:
    • Connolly or Bridge or Weir leather interior
    • Coolaire air-conditioning system
    • Bucket seats with tilting squabs to allow access to the rear seats
    • Radiomobile radio-stereo 8 track cartridge tape player, four speakers, electric aerial Optional Phillips AM/FM radio cassette player or Phillips AM/FM radio cassette recorder. Later Blaupunkt Berlin AM/FM radio cassette recorder
  • Engine:
    • Front mounted all-alloy 90° V8, 5,340 cc, two-valves-per cylinder, twin overhead camshafts per bank. Engine number prefix V540/
    • Bore 100 mm. Stroke 85 mm. Compression ratio 9.0 : 1 (8.3 : 1 Emission Control LFM & LFA)
    • Four Weber 42 DCNF downdraught carburettors. Fuel supplied by SU AUF 412 electric pump
    • Maximum power: not quoted at the time but now believed to be between 280 bhp and 300 bhp. (230 +/- bhp Emission Control /LFM & L/FA). ‘S’ spec engine believed to be 306 bhp @ 6,000 rpm
    • Maximum torque: not quoted at the time but now believed to be 320 lb.ft @ 3,000 rpm
    • Air Injection System: AC Delco air pumps from 1977
    • Twin catalytic convertors on Emission Control /LFM & /LFA
    • Ignition System: Lucas ‘OPUS’ Mk 2 electronic.
  • Transmission:
    • Automatic: Chrysler Torqueflite 3 speed automatic
    • Manual: 5 speed ZF. Hydraulically operated 10½” Borg and Beck single dry-plate diaphragm clutch. Additional cost option from 1975
    • Final drive: Salisbury hypoid bevel with Powr-Lok limited slip differential. Final drive ratio: 3.31 : 1 (manual), 3.54 : 1 (optional and NA spec), 3.07 : 1 (automatic)
  • Steering:
    • Power assisted Adwest rack and pinion, 2.9 turns lock to lock. Turning circle 11.58 meters
  • Wheels and tyres:
    • Bolt-on, 5 stud GKN Kent 15 x 7 ” light alloy wheels
    • Avon GR70 VR15 radial low profile tyres
  • Suspension:
    • Front: Independent. Unequal transverse wishbones, coil springs and co-axial telescopic Koni shock absorbers with an anti-roll bar
    • Rear: De Dion axle tube located by parallel trailing links and a Watts linkage. Coil springs and double-acting piston shock absorbers
  • Brakes:
    • Front: Girling, ventilated discs; 10.75″ diameter
    • Rear: Girling, Inboard ventilated steel discs, 10.38” diameter
    • Tandem master cylinders and dual vacuum servo assistance
  • Dimensions:
    • Length: 4,660 mm
    • Width: 1,829 mm
    • Height: 1,327 mm
    • Wheelbase: 2,610 mm
    • Front track: 1,499 mm
    • Rear track: 1,499 mm
    • Kerb Weight: 1,727 kg
    • Fuel tank capacity: 95.4 litres, 114 litres from October 1977
  • Performance:
    • Acceleration: 0-60 m.p.h 6.2 seconds (auto), 5.7 seconds (manual), 7.7 sceonds (/LFM spec)
    • Maximum speed: 146 mph (automatic), 155 mph (manual), 135 mph (/LFM spec)
  • Price at launch:
    • September 1973: £9,593
    • August 1974: £11,349
    • 1975: £12,795 1976: £15,600
    • May 1977: £16,600, (USA, January 1977: $33,950)
    • October 1977: £19,000, (USA, July 1977: $37,500)
    • January 1978: USA over $40,000