Metal side goes down. You should use some copper gasket seal when installing. Spray or brush on the copper gasket seal and let it sit for approximately 60 seconds, until tacky, then slide it over your guide bolts. I took some 6" bolts and cut the hex head off, ground the jagged edges smooth and screwed them into two of the head bolt locations. This provided me with a good guide for the gasket and ultimately for the head. Once the head is on, put in a couple of the original bolts and remove the guides. Make sure you pay attention to your torque specs and tightening order on the head bolts.

Good luck.

Whats down in the well comes up in the bucket, so watch who's KoolAid you drink.