block chevy? spent today putting new valve seals in my friend's 1986 chevy truck. 305, 2 barrel. went to start it and it barely ran and died. Backfired several times when trying to start. It worked perfectly fine before. Plug wires are on right, distributer hasn't moved. wasnt sure about the lash so i went 1 1/2 turns past zero lash. Did i use too much lash?