Strange 318 Block

68-73 318 are the ones I use.
They are slightly stronger at the main webs, "even Ray Charles can see that, and he's blind" They also seem to be candidates for a 4"-4.04" over bore.

4 ear mounts, here nor there, still stronger in that depot.

I like the idea of measuring between the cylinder cores through a freeze plug hole of a later versus early 318... that's interesting to me and should enlighten the rest who don't know 1st hand or believe.