Chuks said "Autofeather a la DHC-6 works by comparing the torque on two engines, doesn't it? So there's no way you could fit that to a single."
Actually, the autofeather for the DHC-6 works by sensing oil pressure via a pressure switch. Once the autofeather is armed, if Torque of either engine drops below 11 psi (for 2 seconds if the 2 sec delay mod is installed), the propeller feathers.