Since the parts catalogs will lead you to a "dead-end" on the powerhead and adapter plate gaskets.... I'll go ahead and provide you the part numbers for the "latest and greatest" improved gaskets:

832933006 Powerhead Gasket
832934006 Adapter Plate Gasket

NOTE: When torquing powerhead- there has been a torque spec change for the two studs/nuts UNDER cylinder #6. DO NOT torque these two in the final torque sequence (contact me by email if you need assistance here).