408 Stroker Short Block Details: Blueprint Engines

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Talked to them to find out about the KB 416 Pistons used as is, the valve reliefs, the cam used on their long block. With head gasket, cam lift and timing events I should be ok, obviously will be checking it when the time comes. No problem to do additional relief cuts if I need to.
Would you have to be careful with the balance if you had to cut extra reliefs?