The 1967 model year Mustang was the first significant redesign of the original model. Ford’s designers began drawing up a larger version even as the original was achieving sales success, and while ‘Iacocca later complained about the Mustang’s growth, he did oversee the redesign for 1967.'[48] The major mechanical feature was to allow the installation of a big-block V8 engine. The overall size, interior and cargo space were increased. Exterior trim changes included concave taillights, side scoop (1967 model) and chrome (1968 model) side ornamentation, square rear-view mirrors, and usual yearly wheel and gas cap changes. The high-performance 289 option was placed behind the newer 335 hp (250 kW; 340 PS) 390 cu in (6.4 L) FE engine from the Ford Thunderbird, which was equipped with a four-barrel carburetor.