"PEARLITIC MALLEABLE STEEL; SPEC GM 84M; 1.180 IN. LG,SERRATED CENTER HOLE; 48 @SERRATIONS; THREE 3/8-24 @UNF THD MTG HOLES; 2 HOLES SPACED 0.795 @IN. BELOW HORIZONTAL CENTER LINE TO HOLE CENTERS AND 2.754 IN. C TO C APART; THIRD HOLE CENTERED ON VERTICAL CENTER LINE AND SPACED 1.590 IN. @ABOVE HORIZONTAL CENTER LINE TO HOLE CENTER; 1.240 IN. OD AT TOP END OF HUB"