The Edelbrock #61329 E-CNC LS3 cylinder head is a great general-purpose high performance cylinder head for any street- strip LS engine. This cylinder head has a high velocity port compared to stock LS3 cylinder head, making them an ideal upgrade for any cathedral port or 3.89" bore LS application. They feature an improved design and casting that gives cylinder head porters more material to work with compared to another stock head. Like all of our other E-CNC cylinder head, these feature fully CNC'd intake ports, combustion chambers and exhaust ports for improved performance. Compatible with stock style rocker arms.