The Edelbrock 5085 E - 210 Cylinder heads are designed for use with 1955 - 1986 Small - Block Chevy applications. The Edelbrock E - Series cylinder heads are a step up in affordable performance from our E - Street line. They feature larger runners for increased airflow, revised exhaust ports and larger diameter springs for higher lift camshafts, making them ideal for a spec series racer and larger displacement engines. The Edelbrock 5028 E - Series Cylinder heads also have as - cast ports and maintain the stock exhaust port location, making them compatible with OEM headers and hardware.