This is the damage formula.
The only things we're changing are the attack's base power and the used attack stat. It should be pretty safe to assume that, on average, stuff like defense stat and other modifiers stay the same. With that said:
what we care about=power*attack
One move's base power is 50, and it uses an attack stat of 134 to calculate damage, so its "what we care about" is 6700. The other move has 80 and uses an attack stat of 94, so its "what we care about" is 7520. Therefore, use the special attack, until you get a stronger attack like flare blitz or fire fang.