Designed for street 1955-86 262-400 c.i.d. small-block Chevys. #2101 is stock replacement/street legal part for 302, 327 and 350 V8s with OEM 4-bbl. or Edelbrock #1400 carb; 1966-72 (1973 non-California) cars, 1966-83 trucks and Suburbans; except stock equipped EGR. #3701 is stock replacement/street legal part for 305, 350 and 400 V8s with OEM 4-bbl. or Edelbrock #1400 carb.; 1972-86 and GM corporate engines with 350 V8s; 1981-86. Performers accept late-model choke, waterneck, air-conditioning, alternator and H.E.I. Has provisions to add oil fill tube. Not for 1987 and later cast iron or Chevy Bowtie heads. Will fit 1987 and later stock aluminum heads.