there is 28.? some grams to a ounce, so the new pistons would be around 2/3 of a ounce lighter than the old ones. BTW, does the piston wieghts you furnished include the wrist pins on both or not? Are the rings the same sizes on both sets of pistons, IE 1/16, 1/16 , 3/16 or are they different sizes like 5/64 on one set and 1/16 on the others?