from 1981 to 1985. The Malaise era 380 SL was the least powerful of the US market R107 roadsters. North American market SL and SLC models retained the "protruding" 5 mph bumpers, even after the wisdom of the law was reconsidered in 1981. US gray market sales The more powerful 500 SL with a 5.0 liter engine, produced from 1980–1989, was not available in the US. This drove many customers to obtain the European specification car in the "gray market." Finally, a more powerful version was available from the factory, from 1986 to 1989, the 560 SL. It was exclusive to the USA, European, Japanese and Australian markets. Despite the larger 5.6 liter engine of the U.S. 560 SL, the forbidden Euro-spec 500 SL was the fastest production 107 produced (mostly because of the lack of emission restraints). The 500 SL was published by Mercedes-Benz as having 0-60 mph times of 7.4 seconds for a top speed of . Torque for the 500 SL is at 3200 rpm and for the 560 SL at 3500 rpm. Mechanical troubles Model years 1975 and 1976 450 SLs suffered from vapor lock and hard restart because of the under-bonnet position of the catalytic converter. Starting in MY 1977, the catalytic converter was moved to replace the resonator, located just behind the transmission in the exhaust system. The 380SL/C engine came with a single row timing chain from 1981 through 1983. These early 380 models were plagued with chain failure problems and the problem was corrected by Mercedes-Benz, free of charge. Some models, however, escaped retrofit and may at some point fail as a result. MYs 1984 and 1985 came with a double row timing chain from the factory to address this issue. Another problem area for late 450 SLs was the automatic climate control system. Based on a "servo," which controlled coolant flow to the heater core, as well as vacuum to actuate the vents in the interior of the car, the system proved unreliable. It was installed on 450 SLs through end of production in 1980. Models produced prior to 1978 had a manual climate control system, 380SL models produced from 1981 received a more reliable automatic climate control system. South African assembly Both the SL and SLC models were also assembled in South Africa by UCDD (United Car and Diesel Distributors) for the captive domestic market from early 1977 (on a