I have an couple of HD7950 and they can pull like 25 MH/s at Ethereum Classic. Revenue is like $1 a day. Power draws like 150 W if you modify the BIOS. Profit $0,63.

If you have them you can use them, but don't go buy some in this market. You'll probably overpay for them (like all GPUs), but they will be like the first ones to get unprofitable.