The piston 12E uses 305 horsepower, when you put the Allison engine in, it is derated to 301 horsepower (4 HP less, because the cooling fan drive for the piston engine is removed from the transmission during turbine conversion)
The 206A/B series ships use 317 horsepower...
The 500D uses 375 horsepower....
The M/R system on the Hiller is just better for lifting, but it don't go fast....