Andrews Camshaft Upgrade Kit 54N for Harley Twin Cam 99-06 Eliminate spring powered chain adjusters Engines converted to 2007 type cams and chain drives will have higher output due to less power loss from older spring powered chain tensioners. Instead of the original spring adjusters, new roller cam chains use engine oil pressure to maintain proper chain tension Camshafts on all 99-06 Twin Cam 88 engines (exc. 2006 Dyna) can be updated to new style roller chain drives