In 1966, the base-model Porsche 911 saw several enhancements as the factory refined its production processes. Key updates included the transition from Solex to Weber carburetors powering the same air-cooled, rear-mounted, 2.0 L flat-six engine, which improved performance and reliability, and the "Type 901" five-speed transmission became more common, moving toward standardization over the four-speed offered as standard before. The interior received better materials and finishes, while the body saw improved panel fitment and chassis rigidity to address issues from the 1965 models. Additionally, electrical components and wiring were upgraded for greater reliability, fewer electrical problems, and an expanded color palette and improved exterior trim quality were introduced. The base model Porsche 911 would continue for model year 1967, however, in late 1966, Porsche introduced the more powerful 911S.