4 of the cylinders have two sets of numbers. I guess that's were it was double checked a bit lower after the first check showed a little thinner than normal (but still very thick.) As seen, the thinnest spots were between cylinders. No problem with taking it .080 over. In fact, I would be confident taking it out to .100. Even at .100 over the thinnest spot would be .165, with the thrust loaded walls much higher than that

Test was done by USA Racing Engines in Houston, Tx.

David Cole

Did you also visually check between the walls, with the frost plugs out that gap between #1 and 2 cylinder should be about .013" to verify the sonic check.
4.90" bore spacing minus half of the 4.36" bore for two cylinders (ie: 4.36" total) leaves .540" between the bores. At .270" each or some combination where both equal .540" the walls should touch each other inside the water jackets.

That's a pretty thick block! Wonder if that's typical for any 68- early 70's 429/460?

I'm thinking it's pretty typical of the C8, C9 and D0 blocks. Prob the earlier D1 blocks as well. They made the D1 blocks from 71 through 76 or so, but the earlier ones prob are thicker due to less core shift and mold wear.