I need Big Block Chevy valve cover bolt pattern please.

[Samckitt]

A guy I work with (drag racer) has a blown/injected/big block that one of the nozzles is in line with one of the valve cover bolts & he wants to make an adapter plate like (small block Chevy perimeter to center bolt) to move the bolt he has interference problem with. Does anyone know the bolt pattern for the valve covers so he can make his adapter plate?

Thanks.