Greetings, I have a 1979 Chevy LUV 4x4 with a 1.8L engine. I just went through the head gasket replacement on it and did a carburetor O/H (Hitachi piece seems to be a pretty bad design). I had the engine set at 6 degrees BTDC on #4 per the book and zip tied the timing chain to the camshaft sprocket before removing the head. Upon reassembly, I have no compression. I did adjust the valves according to the book after I installed the head. If I did get the chain off by a tooth, do any of you have any recommendation on how to fix my problem without endangering my valves - its an interference fit. Pictures of an appropriate allignment of chain and cam and crank pulley would be helpful. Also, what does that pin do in the timing chain (see picture)?