[BruceWilkie]

Originally Posted by Half-Inch Stud

Seems there is need to standardize "critical thickness" measurements in the following block features:

Main Web width:
Lifter Bore wall:
CYL wall sonic after a 4.21 bore occurs:

Thickness/depth around mains and recesses are also significant.
69 400 cap bolt shoulder is @ 2.25" vs 59 at 2.625" ... the cap difference from the bearing surface to average outer perimeter between bolts is is over 1/4" difference.(Higher nickle content too) Main saddle area there is a depth difference thats similar. Recess differences under the dowel area even under the main bolt bosses are not just measurable but clearly visible.

When you start to study the 59 block up close in person you are left thinking... in 59 they probably knew they were going bigger in the future...and you have to consider... were they were undecided about bigger bore or bigger stroke with bigger mains?... they certainly had left enough room for 417-421 inches either way and still be bigger than Ford Chevy and Mopar at that point. (406 ford 409 chev and 413 mopar)