You would be wise to not use the auto head gasket that comes in a kit. Spend the bucks for an OEM Mercruiser HG. I would also go with OEM cam waterpump seals, and crank oil seal.
Do they really put auto head gaskets in those kits? If the motor never saw use in a car, why would they ever do that? I know it's a 460 head but that makes no difference because the engine kit should be designed for a boat.
Chris is exactly right. The auto head gasket is designed for use in an engine with a iron head and block, not the Al block of a 470. The OEM gasket was designed with some extra sealing features. I do know that the guys that hot rod the 470 (including a land speed racer) say the OEM head gasket holds up much better.
Rebuilt a 170hp 3.7 over the past winter. Not a difficult job, but take your time and employ quality parts. Make sure you check the head for cracks when having the valves re-ground and re-seated. New valve stem seals a must. Get the permatex aviation sealant #3 for your gasket work, great stuff. Oil pump alignment via distributer shaft is a big must; don't screw this up.
