Actually 3 oz. Still a bummer...........

I own both motors and its weird they're so close in weight. The 120 is physically much bigger than the 75. I was quite disappointed with the 75 when I first got it. But it runs well and has good power for what it is, a 60 sized engine. Sad thing is the 91fx weighs about the same and has much more power. Anyway, since I have it I've used it on a couple of planes and its fine for what it is.. I have the 61 fx also, which weighs close to the same as the 75 but the 75 is significantly stronger. If I had it to do over I'd buy the 95 AX, but since i paid for it I'll use the 75.

Anyway, back to the OP, I use a 17-6 sport apc on my 120AX. Good prop for the motor.