Exploding water pumps? Difference in early 273 water pumps vs later 1970s 318 pumps
Something that always makes me wonder.
If you need 1/4" for everything to line up correctly.
Make 1/4" spacers for behind the crank andwater pump pulleys and same with the alternator, ps and AC brakets.
Move everything 1/4" inch toward the radiator!
Also if there is interference between alt and head, can't you grind / machine off the offending area of the head?
Or perhaps longer or shortest belt to position the alternator in a slightly different position?