Pitman Arm Question?

I am building a 1974 duster and doing a Manual Steering Swap on it. I bough a rebuilt Manual Steering Box a long time ago at a swap Meet and finally getting around to using it on this build.

My Issue is I am having a very hard time finding a Pitman Arm that fits the output shaft. I have tried a Moog K7074 (For 70-72 Dusters) and a Moog K7075 (For 73-76 Dusters) Both just a bit too small to fit on. And a Moog K7076 Which is way too big.

Someone told me I may have ended up with a B-Van or C Body Steering Box. Anyone know how I can Check to verify? And also is there a Pitman Arm Available that would work with this Box and an A Body?

The measurement across the Big Splines on the output shaft is 1 1/8 in.