Tap, Tap, Tap...

Overfilling the oil can cause aeration and prevent a lifter from pumping up. This could cause a tapping noise. When you changed the oil did you put 5 qts. in with the change of the oil filter? If it`s a new cam and lifters, don`t be surprised if it isn`t a lifter as there have been a lot of problems reported with many of the MP kits.