Mercruiser 470 Warped Block/Head

[DBG]

So i just replaced my head gasket on my '78 Mercruiser 470. Noticed the old one looked undamaged. Now that the new one is installed, the engine is still leaking around the head gasket and runnin hot. I think either the head or block might be warped. Anyone know whether either is a common problem? And does anybody out there have anything to say about the pour-in sealers aka Blue Devil, Steel Seal, etc? Any opinions are welcome and appreciated... Thanks!