I have a set of diamonds, .040 over, very few miles, had to replace block for a line bore issue and used a standard bore block a am not boring it out to 40.
Let me know if your interested
I can shoot you pics,after cleaning them up there are a few with scuffs on them.
Was told if your building a top of the line motor don't use them.
If you are putting a motor together to drive and and not kill they would be ok.