ATK High Performance Aluminum Cylinder Heads for Small Block Chevrolet

Outfit your top end with a set of these assembled ATK High Performance aluminum cylinder heads for small block Chevrolet. They're cast, machined, and assembled with A356 aluminum alloy. The heads feature the latest port designs for maximum efficiency and increased power, and improved stock exhaust port location for better header fitment. ATK High Performance aluminum cylinder heads for small block Chevrolet include: * 2.020 in. stainless steel, swirl polished with undercut stem intake valves * 1.600 in. stainless steel, swirl polished with undercut stem exhaust valves * Manganese bronze valve guides * Alloy valve seats * 1.437 in. diameter valve springs (.600 in. max valve lift) * Chromoly 7-degree valve spring retainers * Single groove 7-degree valve locks * Valve spring locators * 5/16 in. flat pushrod guideplates * 3/8-24 in. rocker arm studs Show Less