New McLeod SFI approved flywheel for LS based engines with T56 transmissions. Flywheel is 30 lbs.  This is what's considered the "Flat" LS style flywheel.  Would be a factory upgrade for the following:

97-04 LS1/LS6 Corvette
98-02 LS1 Camaro Z28
98-02 LS1 Firebird/Trans Am
04-06 LS1/LS2 GTO

NOTE : Requires LS1/LS6 style clutch and pressure plate, meaning it doesn't work with the LS2/LS3/LS7 style clutches, nor LSA/LS9 clutches.