Considering overheat is better, and the IV difference is quite minimal really when directly compared in combat.
I would say...its possible.
Overheat is strong.
But i think both could be used to equal effectiveness overall.
Charizards fire type quick move would help however if you plan to use him to counter things weak to fire, which is the main reason to use fire types.
I would recommend powering and using both, and may i also suggest if you really want to pick one or the other...just pick whichever pokemon you prefer, who do you think is cooler? Use it