3 speed/4 speed clutch?

I would expect that a light duty 1/2 ton D100 with a \6 is going to have the standard 10" clutch (not to be confused with a 10 1/2 used on v8's). I would only expect to see the 11" clutch in a 3/4 ton truck. You will need to measure the disk to be sure. The splines on the disk and input shafts of the trannies are the same in either case.

The 10" clutch bolts to the same flywheel as the 9 1/2" clutch used on a \6 cars. If you have the 10" (they are listed on NAPA online #NNC MU15251) you will be able to use the A833OD and it's bell housing.

FWIW, when I rebuilt the \6 in my 68 Barracuda I installed an A833OD in place of the 3spd at the same time. I ordered a 10" D100 \6 clutch from NAPA. It worked perfectly.