Do You (or Your machinist) have access to a borescope?... besides sonic tests a borescope
inserted into the 'freeze plug' openings can reveal a ton of info on INTERNAL casting integrity, Read ability to flow coolant :D
By all means do so, 'nip' a piece off the block and have the Nickel content checked...
A bit more $, But, 'rule of thumb', 1/2-3/4 % nickel content = no 'flexy flyer' Main saddle
alignment or 'bore wiggle' when pounded on :D
With respects I humbly disagree Sir, I would not go below .18
Notes on 'thrust sides',
Most all I.C.E's on the planet have a clockwise rotation, (with the exception of some Hondas, and Cummins)...
So...
The Major Thrust Side on the right bank is nearer the exhaust ports, While the Major
Thrust Side on the left bank is nearer the intake ports, regardless I would not go below
.18, EDIT, ON ANY SIDE, apologies .
P.s, subscribed.