trying to identify aftermarket 340 Pistons

dbphemi said
ok ,thanks for the help. I am planning on running the stock x heads . I’d like to go back to 100 percent stock but i’m not sure how it will run on todays pump gas. we have 93 in illinois mixed with 10 percent ethanol.

It will be fine with those pistons, because these engines always measured lower on compression than they were rated. It will be in the 8.5-9:1 range.