https://conceptzperformance.com/ati-performance-ati-super-damper-race-crank-pulley-1000hp-nissan-300zx-z32-ati917755_p_3344.php it is over driven, so if you want one that is under driven they have this one. https://conceptzperformance.com/ati-performance-ati-super-damper-street-crank-pulley-nissan-300zx-z32-ati917754_p_4602.php