1970 ARK Sprite Twin-Cam FIA HTP

Constructed in 1970 by the innovative ARK Racing concern, the ARK Sprite stands as one of the most charismatic and technically interesting British GT contenders of its era. Conceived around the idea of combining the second-generation Austin-Healey Sprite's lightweight proportions with the proven potency of Lotus Twin-Cam power, the ARK Sprite rapidly established a reputation for speed, durability and intelligent engineering.

At its heart lay a highly efficient and reliable Lotus 1,600cc Twin-Cam, dry-sumped and mounted as a stressed member within a purpose-built spaceframe chassis. This sophisticated approach, allied to a close-ratio Ford gearbox, endowed the car with exceptional rigidity and balance. Power was transmitted through a strengthened Ford Anglia rear axle fitted with a Hewland limited-slip differential, while braking was by Girling discs all round. At the front, modified Triumph Herald suspension was employed, utilising bespoke wishbones unique to the ARK design.

The chassis was clothed in a Smith and Deakin glass fibre body, subtly widened to accommodate broader wheels and a more purposeful stance. Bespoke alloy doors were fabricated, underscoring the car’s competition-led ethos and attention to weight-saving detail.

The ARK Sprites competition career began in earnest in 1970, quickly demonstrating its credentials with a strong second place on its debut, followed by appearances in demanding international events including the Nürburgring 500km, the Thruxton GT, and a six-hour endurance race at Jarama, Spain – a formidable programme that cemented the car’s reputation during its first season.

However, it was in 1971 that it secured its place in British motorsport folklore. Driven by John Banks, with shared duties from Chris Smith (later of Westfield fame), the car achieved a remarkable overall scratch victory at the Birkett Six Hour Relay Race – one of the most storied events on the UK racing calendar since its inception in 1951. Covering an astonishing 217 laps at an average speed of 86.8mph, the Sprite became the first car ever to exceed 500 miles in the event, a landmark achievement that remains one of the Birkett’s defining moments.

Subsequent regulation changes curtailed an intended full international campaign, prompting a return to UK-based GT competition, but the ARK Sprite’s legacy had already been firmly secured as one of the most successful and innovative Sprite-derived racers of its time.

Recently issued with FIA Historic Technical Passport (HTP) papers (Class TSRC16) valid until 31st December 2034, this evocative and highly significant British GT car presents a rare opportunity for a new custodian. Eligible for a wide range of prestigious historic race meetings, Modsports, Hill-Climbs and Sprints, the ARK Sprite offers the chance to return a true piece of UK motorsport history to the circuits where it earned its reputation more than half a century ago.

Current full specification:

• Chassis: Full space frame, with alloy panelled centre section, now foam filled, full cage which is part of the chassis.
• Brakes: discs all round, alloy callipers all round, all fully Aeroquiped, adjustable balance bar inside car.
• Body: Full fibre glass with arch extensions, one-piece front inc. doors, pollplex front screen, perspex sides and rear windows.
• Suspension: Independent front, live A frame rear axle with parallel top links, all rose jointed, front Trax Spax Shocks, rebuilt alloy Armstrongs.
• Fire System: new foam system (discharges into compartment)
• Seat Belts: 6 point TRS
• Engine: Lotus twin cam 1,600cc, all steel, dry sumped, (fitted with new head), 1.7 inlet valves, 1.4 exhaust valves, all Cosworth, inc buckets, phase 4 type cams, vernier timing wheels, 45 Webers, L block, Omega pistons, 83.5 Cosworth con rods, Farndon crankshaft ground .010”/.010”, large tooth belt, drive water pump, pinto impeller, 5 port dry sump pump, custom made exhausts.
• Plumbing: alloy 1.5 gallon oil tank, alloy swirl pot 23lbs rad cap, Aeroquiped water bleeds (rad swirl pot), new alloy rad, 12 row oil rad, Bendix fuel pump, new 16 gallon/72 litre alloy fuel tank.
• Gearbox: New Ford 4 speed Pro Syncro straight cut box, close ratio, (rated for 250bhp), Rose jointed gear leaver.
• Rear Axle: Ford 105 E case, braced, Quaife lsd unit ratios 4.1-4.7-5.1
• Wheels and Tyres: Alloy 13” dia 8” fronts 10” rears, Avon A37 all weather tyres.
• Electrics: Elliot rev counter, water, oil temp, oil pressure, Ark Racing starter, and small flywheel, new 5.25” 2 plate clutch, Ark Racing clutch release bearing system.
• Steering: alloy quick ratio steering rack, alloy mounting blocks.