Been trying to locate the max angle specs for the Spicer 1000 series u joints. I can find the specs for 1210, 1310, etc, but not the smaller 1000 series. Yoke size for the 1000 series can be had in a common 1" bore with a .250" (1/4") key way, which is what a lot of people seem to use on the lower powered buggies (30hp and below). Smallest bore size you can easily get a 1310 in is 1-1/4" bore with a 1/4" key way. However, 1-1/4" is not as cheap as a 1" axle.

1310 series has a max angle of about 30⁰.
Continous torque is 130ft/lbs
Max continous is 790ft/lbs