Assembling two avalanches at the same time. For the first one I bought a different brand header which is quick and easy to install. Everything fitted perfectly and was tightened. I installed them on another and ran into a few problems. First, the bolt holes on the headers do not line up with the holes on the cylinder head. Second, when I put them back in place, I couldn't reconnect the spark plug wire to cylinder 5 because the distributors were routed right in front of it. Eventually I…