To 65 Autolite: Sorry I'm late getting back to you regarding the thermostat "pocket" question. My intake manifold has a cast date of 5A25, or January 25, 1965 (my car's scheduled build date is February 16, 1965). The intake manifold has a recessed “lip” all the way around the inside perimeter of the thermostat “pocket,” which is obviously where the thermostat fits. And the matching thermostat "cover" has a perfectly flat surface. Of interest, I have another manifold on the shelf (5H24/August 24, 1965) that has only a flat surface around the perimeter of the manifold's thermostat “pocket,” but a recessed lip around the inside perimeter of the thermostat "cover" that bolts onto the manifold. Thanks, Ron...