Edelbrock Manifold EFI Pro-Flo XT BB Chevy Rect Port Heads As CastEdelbrock part #7136 Pro Flo XT EFI intake manifold is engineered for high performance 396 502 c. i. d. Chevy V8's with rectangular port cylinder heads. A large plenum and tapered runners deliver maximum horsepower and broad torque throughout the rpm range (1500 6500 rpm). It features a 90mm throttle body opening for maximum performance. Aesthetics were also a major consideration in the design, offering enthusiasts a custom look. The Air Gap design