"ALUMINUM,SPEC GM4321-M,6.700 IN. LG,6.440 IN. W,0.880 IN. THK,FOUR 0.469 IN. DIA MTG HOLES,HOLES SPACED 5.760 IN. C TO C ON LG AND 5.500 IN. C TO C ON W,FOUR 3/8-16 @UNC 3B THREADED HOLES. TWO HOLES SPACED 0.340 @FROM HOLE CENTER LINE TO CENTER LINE ALONG W,AND 4.000 IN. C TO C BETWEEN HOLES,TWO HOLES SPACED 0.060 IN. C TO C BELOW THE TWO MTG HOLES ALONG LG,HOLES SPACED 2.320 IN. C TO C"