here's my suggestions
your helm is probably keepable til raids but if you're aiming to get block capped (which from what I've been hearing is your priority after def MINIMUM(edited so frog wouldnt eat my face)) then try to get
http://www.wowhead.com/?item=37135 out of heroic nexus
necklace I'd suggest buying
http://www.wowhead.com/?item=37646 off your AH you can usually find tons of them up on a good server for cheap. Or you can make
http://www.wowhead.com/?item=42646 or the badge necklace if you're farming heroics
shoulders are alright, Im personally not a fan of expertise I try to weed it out on my gear in favor of other things. Theres not a lot of options for shoulders pre naxx so either stick with those or get
http://www.wowhead.com/?item=37635 since they have pretty high % mitigation for getting block capped
cloak is fine but I'd trade your chant of 225 armor for titanweave (16 defense rating) even though your over cap defense isnt too shabby and like I said I reccommend getting block capped after def cap.
for chest:
http://www.wowhead.com/?item=37052
http://www.wowhead.com/?item=37735
http://www.wowhead.com/?item=37658
http://www.wowhead.com/?item=44198
the last two Im personally not a fan of since I dont much care for hit rating and expertise and a lot of their itemization is wasted on it. I reccommend getting one of the first two or saving your badges til you can afford t7 chest.
for bracers:
http://www.wowhead.com/?item=41116
http://www.wowhead.com/?item=44341
http://www.wowhead.com/?item=37040
http://www.wowhead.com/?item=37682
http://www.wowhead.com/?item=37620
Ideally you should just farm old kingdom for badges and gear until the last ones drop. The BS ones dont compliment your gear very well considering how defense heavy they are and how far you are over cap.
Weapon:
http://www.wowhead.com/?item=37260
http://www.wowhead.com/?item=37401
both are good options and the second is the best pre raid tank weapon available. You probably wont replace it for some time into raids. Also reccommend dropping mongoose for regular (not greater) potency. Mongoose has scaled very poorly imo.
I'd replace your empyrean tortoise with one of these
http://www.wowhead.com/?item=36993
http://www.wowhead.com/?item=37220
http://www.wowhead.com/?item=42341
http://www.wowhead.com/?item=37872
Pants:
http://www.wowhead.com/?item=43500
http://www.wowhead.com/?item=37688
http://www.wowhead.com/?item=37292
The middle one is almost prefferable to the epic in some ways due to the percentage mitigation it gives. If you're trying to get block capped it's not a bad choice, but overall I'd say the epic wins.
Belt:
http://www.wowhead.com/?item=37241
http://www.wowhead.com/?item=40689
I personally prefer the badge belt but either are great
http://www.wowhead.com/?item=37645
http://www.wowhead.com/?item=37862
http://www.wowhead.com/?item=44183
http://www.wowhead.com/?item=37671
the first two are really not preferable to me since itemization is again wasted on hit/expertise. I would ideally get the kirin tor gloves, but if you dont have the rep buy the last ones since they are all over any decent AH and usually cheap to boot.
Hope this helped some! People who are more heavy into mechanics than me feel free to correct any misinformation

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