in 1972 which used a Lotus 907 belt-driven DOHC 16-valve 2-liter straight-4 producing 140 bhp (54.6 kW/liter, 1.20 bhp/cid). All of these, although mass-produced, are also of relatively limited production, so it is argued that the first widely available and popularly priced mass-production car with a four valve per cylinder engine was the 1973 Triumph Dolomite Sprint. This Triumph used an in-house developed SOHC 16-valve 1,998 cc (122 ci) straight-4 engine that produced 127 bhp (47.6 kW/liter, 1.10 bhp/cid) at introduction. The 1975 Chevrolet Cosworth Vega featured a DOHC multi-valve head designed by Cosworth Engineering in the UK. This 122-cubic-inch straight-4 produced at 5600 rpm (0.90 bhp/cid; 41.0 kW/liter) and at 4800 rpm. The 1976 Fiat 131 Abarth (51.6 kW/liter), 1976 Lotus Esprit with Lotus 907 engine (54.6 kW/liter, 1.20 bhp/cid), and 1978 BMW M1 with BMW M88 engine (58.7 kW/liter, 1.29 bhp/cid) all used four valves per cylinder. The BMW M88/3 engine was used in the 1983 BMW M635CSi and in the 1985 BMW M5. The 1978 Porsche 935/78 racer used a twin turbo 3.2-liter flat-6 (845 bhp/630 kW@8,200 rpm; 784 Nm/578 ft.lbs@6,600 rpm). The water-cooled engine featured four valves per cylinder and output a massive 196.2 kW/liter. Porsche had to abandon its traditional aircooling because the multi-valve DOHC hampered aircooling of the spark plugs. Only two cars were built. Ferrari developed their Quattrovalvole (or QV) engines in the 80s. Four valves per cylinder were added for the 1982 308 and Mondial Quattrovalvole, bringing power back up to the pre-FI high of . A very unusual Dino Quattrovalvole was used in the 1986 Lancia Thema 8.32. It was based on the 308 QV's engine, but used a split-plane crankshaft rather than the Ferrari-type flat-plane. The engine was constructed by Ducati rather than Ferrari, and was produced from 1986 through 1991. The Quattrovalvole was also used by Lancia for their attempt at the World Sportscar Championship with the LC2. The engine was twin-turbocharged and destroked to 2.65 litres, but produced in qualifying trim. The engine was later increased to 3.0 litres and increased power output to . The 1984 Ferrari Testarossa had a 4.9-liter flat-12 with four valves per cylinder. Almost 7,200 Testarossa were produced between 1984 and 1991. In 1985 Lamborghini released a Countach Quattrovalvole, producing from a 5.2-liter (5167 cc) Lamborghini V12 engine (64.8 kW/liter). The Mercedes-Benz 190E 2.3-16 with 16-valve engine debuted at the Frankfurt Auto Show