Firstly, you are wasting some of Arcanine's potential. Arcanine is an attack-strong Pokemon, yet you are using a special attack (flamethrower). You need to replace flamethrower with the undoubtedly best attack-type fire move, flare blitz.
Get this: not only will flare blitz fill more potential with Arcanine (because flare blitz is an attack-type fire move), but flare blitz has both the same accuracy and PP as flamethrower. Here's the big difference: Flare Blitz has an attack power of a whopping 120, while flamethrower has a special attack power of only 95.
Now, the one drawback is that Arcanine will receive recoil damage. But, that is the only drawback. Honestly, given the rest of the positives of this move switch, you should consider switching, regardless.