my mcleod billet steel is 24lbs, and thats .200 thicker than their normal ls flywheel. not sure what a pontiac fw would weigh from them. the aluminum one that i returned was 14-16lbs and it was .200 thicker as well. i will be running 3.73s, 2.66, 3900ish lbs and a 28.5 tall tire. i could go back to the aluminum, but im not sure it will be enough.