Spicer solid small joints only fit the axle end. They won't fit the small yoke on the tranny end so there I use the standard Dana/Spicer. Other brands are phony using a harder rubber on the cups to give the illusion of H.D.
Driveline Service told me that the Brute Strength auto store ones I had brought it in with gave him problems on the spin up to speed. He wore them out, but that balancing is perfect for a 3" factory shaft. If it is balanced it can stand the end play and spin smooth. On the street, it would have probably made noise on deceleration like a worn out joint on a hilly freeway.