From information I have here there were 2 types of 74 versions.
The 74 Coaler B was built as an arctic support craft with increased fuel capacity, enlarge radar in a bulged radome, observation blisters and better navigation equipment. (also it could be fitted with ski's)
The only other type it mentions is a 74 "Madcap" that was an early warning version with large rotodome on the tail.
Not a clue on Fitter2's challenge so I will guess a Cirrus?