Yer right old school , after some digging it was the 350 pistons that we’re available at the time from sealed power the 357p series , I was buying my parts from Ace back in the day and we got to talking about the available options for a stock 350 ho build . Those pistons were all I could find and when I measured the deckheight they were .020 farther down in the hole , so I had the machine shop take that amount off , then I was .010 down just the same from gm


Found this also


One disadvantage of the 357P pistons is that they only have a 1.700" pin height. The pin height or compression distance, as it is sometimes called, is the distance from the center of the pin hole to the piston top. That means that quite a bit will have to be machined off the block decks, in order to achieve the desired zero deck height.