[Frank Benvin]

1964 -336 fixed gear almost 200 sold engines 210HP Continental-IO360
1965 -337 retractable gear, engine driven hydraulic landing gear system
1966 -337A gross weight 4,200 lbs
1967 - 337B gross weight 4,300 lbs - T-337B turbo charged introduced
1968 - 337C gross weight 4,400 lbs
1969 - 337D
1970 - 337E gross weight 4,440 lbs
1971 - 72 -337F takeoff wieght increased to 4,630 - max landing weight 4,440 lbs ,extra engine access door
1972 - Turbo model dropped
1973 - P-337G pressurized/turbocharged intoduced Engines on P-models 225HP Continental TSIO-360 max take off weight 4,700lbs landing weight 4,465, electro-hydraulic gear power pack introduced
1974- long range fuel 131 went to 150 gallons
1977 -radar introduced
1978 - T-337H Turbo model reintroduced
1978-80H

Total skymaster production 2,058 + 332 pressurized versions