GSC Power-Division billet S1 camshafts for the 2008+ STI EJ257B With Dual AVCS. Good for stock frame turbo or up to 500 WHP (GT35R) upgrades. Upgraded valve springs are required; Beehive valve springs are recommended but not required.
NOTE: Due to the lobe size, head castings will need to be filed down slightly for clearance - Please check during install