360 stroker, cylinder wall thickness

Assuming the sonic tester is accurate, my personal decision for street any even drag racing use would be to use it since 1.2 HP per cubic inch is not highly aggressive. You have > 85% of the minimum original wall thickness in the major thrust area, and your minimum thickness now is about 75% of the average wall thickness. And you have > 80% of the minimum original wall thickness in the minor direction. Plus, the minimum thickness you have is 30% thicker than the thickest sleeves commonly found for bores of this size (1/8" thick).... (although sleeve material is stronger).

But I might decide differently if I was going to race it on circle tracks at high constant revs and high constant HP.

And your question about getting a different block is a good one...with .015' thicker walls in a .030" overbore, you could well end up with about the same minimum thickness in one spot.