I think your calculation is wrong.
This is my 3 x R9 270x and 46.49MH/s power i have.
Earning in last 24 hours 1.533089 ETH (dwarfpool)
earn $2 per card i think its not possible.
He have the gtx 970, and not the r9 270x.
With optimal parameters 3 gtx 970 should do 66 MHASH. Mining on a Pool will loose 10%
66Mhash:
http://badmofo.github.io/ethereum-mining-calculator/Gives around 2.5 ETH a day. ($6.41)
The gtx 970 comes with 4GB of ram, and this meens that the profitability will increase when the Dag file is increasing and the 270, 280x cards cannot be used anymore.