The most popular Lamborghini Countach, the LP5000 Quattrovalvole (meaning four valves) was launched in 1985. Commonly known as the QV, or 5000 QV, the Quattrovavole featured the next generation Lamborghini V12. With a longer stroke and larger bore, this 5.2L engine produced 449hp in European carbureted specification. The European spec had two engine variations, one featuring six Weber downdraft carburetors, and one with Bosch fuel injection, which only produced 414hp. The US version featured rubber bumpers and was only offered with a fuel injection system. Due to lack of import restrictions on cars over 25 years old, it is common to see both Euro and US versions trading in the US. As most US cars had their unsightly bumpers removed, the easiest way to distinguish between the two versions is the engine cover. Euro spec cars feature a bulge in the middle to clear the downdraft carburetors, while US versions featured two bulges on either side of the cover. The most common QV is the Euro spec carbureted car, with more than half of total production. The fuel-injected version is slightly less common, but total production numbers are disputed. The Quattrovalvole is the best selling of all the Countach variants, but with only 610 produced, it is still a rare and special car. The LP5000 QV was built until 1988 and was replaced by the Countach 25th Anniversary Edition.