Questions about the Mopar Performance 340 Replacement Block P5007552AB

^ this.
No blocks currently available in big block or small block should be expected to be able to be used as delivered with the exception of Keith Black's. And the KBs you need to carefully check everything just to make sure - everybody's human and there have been issues found with those too. The MP stuff plain sucks. Plan to re-machine it completely, and make sure the shop can check the alignment of the lifter bores.

Anything in particular?