www.QV500.com - Lamborghini Countach Part 5: LP500 Quattrovalvole
 

In September 1984, Ferrari unveiled the replacement for their ageing Berlinetta Boxer, this car having been the Countach's closest rival ever since 1974. The new 380bhp Testarossa certainly looked the part, but Lamborghini countered a few months later with their most powerful Countach yet - the Quattrovalvole. There were no major set-up modifications although marginally wider front tyres dictated some slight suspension geometry changes. Rather, the most significant changes were made in the engine bay where a heavily revised 5.2-litre V12 replaced the outgoing 4.8.
   
Displacement was now 5167cc thanks to a bore and stroke of 85.5 x 75mm, the latter up by 6mm. More important though was the adoption of four valve cylinder heads with pentagonal combustion chambers. Twin 36mm inlet valves replaced the solitary 48mm valves used beforehand while two exhaust valves (of 32mm) superceded the 38.2mm item of earlier models. Considered more attractive than either radically increasing displacement or turbocharging, this 48-valve V12 was undoubtedly the finest high performance engine of its era. Compression was increased to 9.5:1 and six twin choke 44 DCNF downdraught Weber carburettors fitted, output rising to a conservative 455bhp at 7000rpm although the authors old QV was dyno-tested at close to 480bhp in totally standard tune! On its launch, the QV became the fastest production car in the world and without a rear wing, could hit 188mph. Meanwhile, 0-60 took a sensational 4.8 seconds. Visual changes were limited to a re-profiled engine cover that now featured a prominent hump to accomodate the carburettors, all but eliminating any rear vision. Lightweight Kevlar panels were used for the front lid and engine cover. Changes to the interior were also few and far between although there was a mildly reworked central console and glove box. Given its debut during March 1985 at the Geneva Salon, QV's ensured the Countach remained at the pinnacle of high performance motoring.
 
Some distinctive changes were made in late 1987 when Lamborghini substituted the Porsche synchromesh for a ZF-manufactured unit. But it was visually that the 1988 model year Countach's were most easily identifiable, Lamborghini fitting Anniversary-style ventilated side skirts. There was also central locking, improved cockpit ventilation and a better heater, these examples often being referred to as QV ‘88's. Production continued until the summer of 1988 at which point the QV was replaced by the 25th Anniversary, 610 having been completed.