Gorebyss
~Surf
~Ice Beam
~Psychic
~Rain Dance
Surf will get STAB and is useful for losers like Golem. Ice Beam is for those naughty Grass and Dragon types. Psychic screws Fighting and Poison types, and Rain Dance, well, god dammit, do I have to say it?
Huntail
~Rain Dance
~Waterfall
~Crunch
~Ice Fang
Rain Dance helps out with Waterfall and boosts speed, the same thing Gorebyss's Rain Dance does with Surf. Crunch is for Ghosts and Psychics. Ice Fang is just Ice Fang.
As for EVs, give them both 252 in their respective Attack stats, 252 in Speed, and 6 in HP.