Changing a WotLK DPS Death Knight to a Cataclysm Tank DK?

[Letheria]

So, I'd like to change my Death Knight to a tank because A: I don't play him that often, and B: When I do play him, I'd like to maximize my time. Tanks seem to be at a premium, so I think I'd like to try him as Blood. I have him in full Tier 9 DPS currently, with some minor Tank-like upgrades.

Is it possible now to run him into Randoms as a tank right now in that kind of gear? I have extensive experience as a Warrior tank, with some eperience as Blood early in WotLK. So, I think my playstyle will be fine, I'm just concerned about his gear.

[Ozonekiller]

Wait, what level is your DK?

[Letheria]

81. Just looking to level through Dungeons. He's my ore farming toon, and is also a blacksmith.