Complete timing chain tensioner update kit. Left & right converts engine to latest design oil pressure fed tensioners. Right-side cam tower oil line requires an adapter for 1973 and earlier engines to ensure proper spacing and to help prevent oil line breakage. 1968-80 updates, if the older chain wheel supports are used, then two chain wheel support spacers are necessary. Replacement version: 930.105.509.00(left support), 930.105.510.0 ) right support). Or 930.105.513.00 spacer bushing (left and right), required for installation.