I don't need to tell you guys what to do...... But what "I" would do is check the net lift at the valve(with the correct lash), then double check the spring installed height and see what the actual open/closed pressures are, along with verifying the coil bind height.

A fast rate .421/.426 solid cam with 1.6 rockers is going to be challenging from a spring pressure/rpm/durability standpoint.