BUV20 good or bad opportunity ?

I've been investigating an old motor controller unit and found it uses a BUR50S transistor for its motor PWM, that's a 125V 70A rated TO3 with hfe = 15, fT = 16MHz, max dissipation 350W.


Alas there's only one (the controller uses a humongous relay to reverse the motor rather than 4 devices in an H-bridge). I think the thing could form a nice Darlington triple with a BD139->2N3055->BUR50S, should handle 1 ohm loads nicely :), but fortunately I don't have complementary pair so won't waste time on such a crazy idea!