I have the exact same setup. ported 345cc -1's with O-rings. I'm using Flatout Gasket rubberized copper gaskets. The object of the rubberized coating was for coolant leaks, but it still trickled a little. I pulled the heads off, added a smear of silicone RTV around the water ports and slapped them back together. Used the same head gaskets. Works fine. No receiver groove in the block deck. Just bolt them on and go. I believe the SCE Titan series gaskets have silicone O-rings around the ports already, but also have an extra wire in the gasket for the combustion seal. I don't know how that will work out with the head O-rings. I would use plain copper or rubberizes and be done with it.