an adapter plate maybe ? years ago, i fabbed such a plate for a buddy of mine, but he had a pontiac motor and wanted to use ??? headers. it was a simple thing to do. i just counter sunk the bolt holes to attach the adapter to the pontiac heads and drilled and tapped the adapters to his header bolt pattern. then matched the head ports to the header ports. he had plenty of clearance in his gto for this however. i'm guessing you may not have this luxury.