83 degrees would be too hot for me. I try keep my cards under 78, with 75 being preferred.
It would usually be more profitable to mine Litecoin rather than Bitcoin. That said, the difficulty is going up quite a lot in about 17 hours, which will make it less profitable.
Just google bitcoin/litecoin mining calculator to get a guestimate on how much you would earn. Be aware that they don't account for difficulty changes, which do change your profitability quite considerably.