Hey Jimbon! Nice team you have there. Lanturn counters the piss out of my current team so I hope to not have to face you in the near future xP
Well there's only 1 thing I see that could be a potential problem if Tailwind isn't up and that is the lack of speed. In my opinion I think you'd be better off with a different Terrakion set:
Terrakion @ Salac Berry
252 attack/252 spd/4 hp
Once you get a sub off you will be able to do wonders and since I know your a high level player I think you could pull it off ;). I hope my suggestion helps, and if not good luck in the future!