No doubt you will have to shave something , taking .050 off the deck is the same as taking it off the head surface , the intake side of something , the head or the intake , needs to be cut . Now you will have an intake or head that will only work on that specific block. The mistake you made was cutting the block, you should have gotten a different piston , but it's too late for that.
I see this too many times , non mopar versed shops ordering parts for the YEAR of the block they are redoing not realizing they are causing a nightmare for the guy paying the bill.