I put tall covers on mine and found the EGR would not fit, so I went to a local metal shop and got some round stock aluminum.
It was just the right diameter as the EGR and enough length
to move the EGR up. Out of this I literaly whittled a spacer.
Eventually I went back to regular valve covers and still had a problem as the heads are World Products and they have a raised rail. This time a spacer made out of 5mm thick aluminum did the trick. Just trace around the EGR gasket.