they all use the same block and engine architecture- you haven't studied this long enough, or done enough hands-on work, to realize that
if you took all those different AMC/IHC blocks and put them side by side, they'd be identical- the only difference would be, how large the holes were in them, for the pistons, and the crank stroke
the OHC 4-liter would have a difference cylinder head- but otherwise have the same block as a 232 or 258
just like Chevy 265-283-307-327-350-400 all had the same basic block, with varying displacements/bore size/stroke