That might explain why it took so long for me to get a box. They were on backorder when I first tried to buy one and kept pushing back the availability date.
Mine is small spline 1 1/8", but it is a 73+ pitman which connects to the center link pointing down. the 72 down connect pointing up.
I think the part number is k7075 for small sector and k7076 for large sector.
Borgeson sells both versions of the box. 800126 (small sector) and 800127 (large sector)