A little investment in Speed and the rest in HP isn't worth to outspeed WoW Rotom-W (defensive) and kill it? Like this:
Heracross @ Heracronite
Ability: Moxie
EVs: 236 HP / 252 Atk / 16 Spe
Jolly Nature
- Pin Missile
- Arm Thrust / Close Combat
- Rock Blast
- Bullet Seed
or
Heracross @...