Designed for street 396-502 c.i.d. big-block Chevy V8s using general duty oval-port cylinder heads. #2161 is stock replacement/street legal part for 396, 402, 427 and 454 V8s with OEM 4-bbl. carb.; 1965-72 (1973 non-CA) passenger cars and 1966-83 trucks, Suburbans and heavy vehicles; except stock equipped EGR. Unlike traditional chromed or polished aluminum finishes, PermaStar won?t oxidize, fade or turn blue and cleans easily? an industry first for automotive engine components.