Past discussions ask, "are you sure it's the steering box that's worn"? There can be other reasons.

Rebuilders mentioned here:
https://www.stovebolt.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/1266858


"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."