GM 781 cast oval port heads. 2.19/1.88 stainless back cut valves. Unshrouded the valves, short side radius blend. Opened the runners up. Decked to 114cc combustion chambers. Chromoly rocker studs, raised guide plates. Dual spring with damper for solid roller up to 650lift good for 6500rpm. Hardened spring seats on exhaust valves. New valve guides were installed where needed when they were rebuilt. Comes with trick flow chromoly head bolts. They were on a 496 for 6 trips last season. All parts were new when rebuilt. Also have single plane single 4150 carb intake ported and matched to these heads