Tom, you have pictured the mating part, called a pinion flange. Your URL leads to a generic flange yoke that will probably work.
I bought mine per the ERA Manual, and they specify the Spicer branded part as it is proven, strength-wise. See:
Spicer 2-2-459 1310 Flange
Or google: "Spicer 2-2-459" ... lot's of sources. I can testify that it is good for 614 ft-lbs TQ
The stub axles will break first ... don't ask
The OP also needs the specific bolts and locking nuts, if he does not have them.
The dims are here:
http://www2.dana.com/pdf/J300-P2.pdf
Sam