Yes, he is a very viable for singles, as long as you have a defogger or rapid spinner.
He can be a special sweeper or special tank, and on sun teams he kicks butt.
ability: flame body
evs: 252 sp atk; 200 hp; 48 def; 4 sp def
nature: + def; - atk
-psychic/ solar beam
volcarona@ focus sash
ability: swarm ( goes great with focus sash)
evs: 252 speed; 252 atk; 4 hp
nature: + speed; - atk
-quiver dance (set up, focus sash protects, then swarm)
-flamethrower ( more accurate, can't risk missing)
-psychic, solar beam
he works very well with quiver dance, focus sash, and swarm, and good for mono-fire teams against mono-dark/ psychic.
Hope I Helped!!!