The Edelbrock C-66-O Dual-Quad #54201 is a dual plane intake manifold which combines dual four-barrel excitement with a well-mannered street manifold. Designed for 396-502 c.i.d. Chevys V8's with large oval-port cylinder heads (1975 and earlier) or Edelbrock Performer/Performer RPM heads. Tests confirmed smooth, consistent part-throttle operation with a 25 hp gain over Torker II and a torque gain of 30 ft-lbs. over Performer. Includes metering rods to calibrate Edelbrock #1405 carbs. Carb center to carb center is 6-7/16". Use with Performer-Plus cam/kit #2162 for low-end torque or Torker-Plus cam/kit #5062 for top-end power. Will not fit tall-deck truck blocks.