That packet is insulation to keep the valve noise down. There or not there, your option. Factory stock. Be sure to soak the valve stems in Marvel Mystery Oil or the witches brew of your choosing, then take a half inch socket extension and a hammer and bang on the rocker over the valve stem to make sure the valve moves. You can tell the stuck ones because they don't make a boing sound, rather a thunk sound. This until you have chemicalled them into submission. Just finished replacing a seriously bent push rod in the second 383 in a row that had sat for too many years. Always a good idea to remove the valve covers and perform the above soak, and hammer plan before starting the engine the first time. The previous B block spit out the valve lifter after bending the push rod. This kills all the oil pressure in the engine until you plug that hole up with the errant valve lifter. Current 383 retained the lifter but 8 cylinders working is better than seven. Both push rods bent in exactly the same place. They are sort of the "Fuse" in the valve system. Larry W Jett 950 Woodside Road Suite 4 Redwood City CA 94061 650 368 3966 [Non-text portions of this message have been removed]