Two sets of NOS Aluminum pistons from Toledo Manufacturing for $280 total One set is marked 1949 Pontiac diameter is roughly 3 1/4" they don't say what size exactly. Box contains 8 pistons, 6 piston pins these might be for a straight 8 Other set marked 1956 Pontiac, Not sure on exact size-Measures Roughly 4 1/32". set contains 8 pistons, 8 pins and back of keepers. These are really nice ones! $250 total for the two sets.