Piston ID & Pump Gas Pistons

Can anybody identify this piston and the compression ratio? It's in a 1971 340 and it is at TDC. I thought it was going to be the stock one but I don't think that this piston would yield the stock 10 1/4 compression.

Also I've read that a compression ratio of 10 is the maximum for a street machine running on pump gas.


Any recommendations on what are the best pistons, with what compression ratio to run on pump gas in a 69 Dart with a 340? I may end up putting on 1971 360 J heads with 2.02 valves, but I have to have them checked out.