We have to remember Arcanine has a Prevo called Growlithe that also learns moves:
Growlithe: Lv1: Bite, Lv1: Roar, Lv6: Ember, Lv9: Leer, Lv14: Odor Sleuth, Lv17: Helping Hand, Lv20: Flame Wheel, Lv25: Reversal, Lv28: Fire Fang, Lv31: [M481], Lv34: Take Down, Lv39: Flamethrower, Lv42: Agility, Lv45: Crunch, Lv48: [M514], Lv51: Heat Wave, Lv56: Flare Blitz
[M481]: Special Fire PP: 15 Power: 70 / Accuracy: 100 Effect: [E121]
[Get Even]: Physical Normal PP: 5 Power: 70 / Accuracy: 100 Effect: [E13F]
Now Get Even i remember doubles in power if one of your pokemon fainted last turn, so I could see An Arcanine with this:
Arcanine @ Choice Scarf
EVs: 252 Atk/248 Spd/8 Either Defense
Justice Heart/Flash Fire
Adamant Nature
Flare Blitz
Close Combat
Wild Bolt/Crunch
Get Even/Crunch
Looks like a pretty good revenge killer to me. Outruns +1 Jolly Gyarados and OHKOs/Forces out with Wild Bolt. Crunch kills Shanderea. Flare Blitz for STAB and Close Combat Smashes Rocks.