Rings for KB pistons 4.080

Ask the shop what piston-to-bore clearance was used. Or, if it apart, check it yourself. Those rings should be fine if all else is right. Never have had a ring seal problem of any type with moly top ring sets like the Sealed Power ones in a coupla dozen assemblies.

Was the break-in with synthetic oil perchance?

I think I am in the minority but the Total Seal rings I used once in a rally car 4 cylinder engine wore the bores a lot faster; the ring tension is a lot higher, and so is drag in the bores. So I don't use them anymore. And if you don't use torque plates on the block when boring and honing for them, I suspect you lose a lot of the benefit anyway.