What are the sonic test numbers a block should have? I am looking at a 440 with 55 over pistons.

The numbers are subjective depending upon the ultimate purpose. Which is? And what numbers do you have?

If you can keep all the numbers above .125 after boring then you're lucky. Ma Mopar didn't know much about quality control in the 70's. Most blocks have at least one thin hole, sometimes two are thin.

Andy , what numbers do you usually see when you are looking at a block before you bore? I am going to sonic check some blocks this weekend just looking for a number that is a go no go.

Your other post indicates you intend to race with this block. Look for a block that is at least .200" on the major thrust sides. I recently checked 11 blocks before I found two like that. The thinnest piston pin sides in those blocks were .147" and .163", thinner than I wished for but acceptable.

It is hard to find a block with all major thrust sides greater than 0.200. Maybe 1 in 10 would be that thick. Most people don't have 10 blocks to pick from!

If we find .180 at the thrust side at finish bore we consider it to be a great block.

AndF & B G Racing, true and true.

So unless you have a mountain of blocks plan on sleeving at least one hole.
R.