If you don't have at least .125" between the end of the starter drive and the flexplate, you're asking for trouble. These spacers allow you the clearance needed to make your lightweight flex plate live. Includes a .030", .035", .045", .055" and .070" spacers. S/B Chevy.
-74: For use with '55-'85 two-piece S/B Chevy crank
-86: For use with '86-Up one-piece S/B Chevy crank