It will be interesting to see Blackout's power usage, but the Dragon miners went from a hair under 900W @ 1TH/s when they used 4 boards to 1150W @ 1TH/s when running 4 boards. I'm guessing these will pull somewhere in the neighborhood of 1300-1400W at 1.2TH/s. Of course the Dragon miner has a much better case design, so the AMT one might run a little worse as everything in there is going to be toasty warm.
Alright where do we start... Airflow.. Boards...Backplane.. Cage.. I know this write up is going to take a few hours so lets go ahead and get started.
Start with some pictures, and a system review. It looks like you're using the 1500W Silverstone Strider ST1500 for a power supply, so there should be some headroom there at least.
Please tell me you at least have a pair of 120mm fans mounted to that cage forcing air through the heatsinks, and aren't just relying on the 200mm fan at the top of the case to draw air out.