By 1974, GM R&D had not succeeded in producing a Wankel engine meeting both the emission requirements and good fuel economy, leading a decision by the company to cancel the project. Because of that decision, the R&D team only partly released the results of its most recent research, which claimed to have solved the fuel-economy problem, as well as building reliable engines with a lifespan above . Those findings were not taken into account when the cancellation order was issued. The ending of GM's Wankel project required AMC to reconfigure the Pacer to house its venerable AMC straight-6 engine driving the rear wheels.