Ken - had this question in mind when I went out today and stopped up the street next to the 62 fleet of a mechanic I know - pouring too hard to waste much time, but did a quick tape compare of mine [58] and his .... identical dimension flanges, and the overall appearance and shape look the same, even the "embossed" depression across the inside of the tub, bolts in same place
so yeah, I'd say 58-66 would be identical, nice to know considering the 58/9 fleet is so rare and there's so many rotten 60-66's in the yards
GM was good about not changing things if they didn't have too, and using small parts from years past on newer designs, that's one of the things I really like about these old rigs
Bill
