instrument panel, O-470-M engines and maximum takeoff weight of ; 225 built. 310C Model produced in 1959, with Continental IO-470-D fuel-injected engines and maximum takeoff weight increased to ; and minor changes; 260 built. Unit cost $59,950 in 1959 310D First model with swept vertical tail, other minor detail changes; 268 built for 1960 model year. 310E Military version of the 310F, designated the L-27B and later U-3B; with maximum takeoff weight of ; 36 built. 310F Model produced in 1961, with extra cabin window each side, pointed nose and other minor changes; maximum takeoff weight of ; 155 built. 310G First model with canted slimline tip tanks and optional six-seat cabin, with maximum takeoff weight increased to and detail changes, 156 built in 1962. 310H Model produced in 1963 with maximum takeoff weight increased to and enlarged cabin interior. E310H Version of 310H with the maximum takeoff weight of the 310G; combined total of 148 310H and E310H built. 310I First model with baggage compartments in rear of engine nacelles, Continental IO-470-U engines and minor detail changes; 200 built in 1964. 310J Model produced in 1965 with minor detailed changes and maximum takeoff weight of . 310J-1 Version of 310J type-certified in the Utility Category; with maximum takeoff weight increased to ; seating limited to four people instead of the 310J's six; and reduced baggage weight limit. E310J Version of 310J with maximum takeoff weight reduced to ; combined total of 200 310J, 310J-1 and E310J built. 310K First model with optional three-blade propellers and long 'vista view' side windows; also increased maximum takeoff weight of with IO-470-V or IO-470-VO engines; 245 built in 1966. 310L First model with increased fuel capacity via fuel tanks inside wings and optional fuel tanks in engine nacelles, also single-piece windshield, redesigned landing gear, and minor changes; 207 built in 1967. 310M Revised designation for the 310E. 310N Model produced in 1968, with revised instrument panel and provision for optional cargo door and fuel; 198 built. Model produced in 1969, with Continental IO-470-VO engines, ventral fin and a shorter nose gear leg. Version of 310P with turbocharged Continental TSIO-520-B or TSIO-520-BB engines producing and maximum takeoff weight of ; combined total of 240 310P and T310P built. Last short-nose model, introduced in 1970, with maximum takeoff weight increased to and detailed changes, from the 401st aircraft fitted with a bulged rear cabin roof