Fits 1986-1992 305-350 Small Block Chevy, 29 LB, Zero Balance, 153-tooth;SFI-approved – legal for use in racing classes that require SFI certification; Choose precision CNC-machined 1045 billet steel for maximum strength and durability or 6061-T6 billet aluminum construction for weight reduction and excellent heat dissipation; Aluminum flywheels feature forged heat treated steel ring gears and replaceable 1045 steel friction surface attached with high-grade fasteners; CAD designed to provide optimum performance and reliability; Available in Internal, External, or Zero (Neutral) balanced versions; Applications offered for a wide variety of engines;