The 365 California replaced the 500 Superfast for 1966. It was the first 365 model, with its 4.4 L (4390 cc/267 in³) V12 based on the 330's 4.0 L Colombo unit but with an 81 mm bore. This later version of the Colombo engine was rated at 320 horsepower, in street tune using three Weber carburettors.

The 365 California used the same chassis as the 500 Superfast but with an evolutionary cabriolet body by Pininfarina. Debuting at the Geneva Motor Show in 1966, just 14 examples were produced[2] (including 2 in right hand drive) before production ended in 1967. Whilst the prototype was built on a 330 GT 2+2 type 571 chassis, production cars featured type 598 chassis. Chassis' were sent to Pininfarina's Grugliasco plant to be bodied and trimmed which were later returned to Ferrari to finish their mechanical components.