“One of the most important parts of an engine assembly is the cylinder head. It holds the key to making power. It also offers the opportunity to make more horsepower. Cams, headers, carburetion can only go so far making horsepower without the cylinder head. However, cylinder heads can be expensive, but this may be one place in the engine where spending the extra money may be worth it.”

“Mopar Engines, Speed Secrets & Racing Modifications For Chrysler V-8 & 6 Cylinder Engines", Chrysler Corporation

“An engine’s horsepower is directly proportional to the amount of air drawn into the cylinder and retained until ignition occurs. By reducing the airflow resistance of the intake and exhaust ports, cylinder filling is improved and engine horsepower is increased directly.”

“Buick Power Source”, General Motors Corporation

“Cylinder heads may not rate a high priority as far as the master plan of the universe is concerned. But if your goal is to build a high-output Chevy for either street or track, then they almost certainly move to the number one spot. Anyone contemplating building a small-block Chevy and not appreciating this will get good results only by being lucky enough to choose a functional set”

“How To Build & Modify Chevrolet Small-Block V-8 Cylinder Heads”
by David Vizard

Cylinder Head Importance

Industry Quotes - Thoughts about cylinder heads in general