While the rest of the world saw 1500s with the compression ratio reduced to 8.0:1, the American market model was fitted with a single Zenith-Stromberg carburettor and a compression ratio reduced to 7.5:1 to allow it to run on lower octane unleaded fuel. With the addition of a catalytic converter and exhaust gas recirculating system, the engine only delivered (DIN) with a slower 0–60 mph time of 16.3 seconds. The notable exception to this was the 1976 model year, where the compression ratio was raised to 9.1:1. This improvement was short-lived, however, as the ratio was again reduced to 7.5:1 for the remaining years of production.