Several people have asked about the specs for the different u-joint sizes. The June 2004 issue of Four Wheeler has them listed.
Series 1310
overall width=3-7/32"
bearing cap diameter=1-1/16"
Series 1330
overall width=3-5/8"
bearing cap diameter=1-1/16"
Series 1350
overall width=3-5/8"
bearing cap diameter=1-3/16"
Series 1410
overall width=4-3/16"
bearing cap diameter=1-3/16"
It list some other relevant data such as load rating also.