Since this is Gen 3 the Special /Physical Split wasn't introduced yet. I don't know if Skull Bash is Specal or Physical and Blastoise has a good Sp.Attack.
I'm Battling the Elite 4 on FireRed and My Blastoise went to level 55.
His Moveset is :
If Skull Bash is a good move and fits to this moveset, tell me which move should it forget.