Significantly improve your engine's Acceleration and deceleration with this Light Weight flex plate. This American made flex plate is the lightest flex plate available anywhere. It is S.F.I. 29.1 certified tested to 12500 RPM. This 153 tooth internal balance flex plate fits Small Block Chevy & Big Block Chevy with 2 piece rear main seal. Zinc plated steel will protect the flex plate against corrosion. Other applications available.