Pretty close- - - -I finally noticed that the exhaust manifold was a big box-shaped item, and I remembered that the primary catalytic converter was in the manifold on some engines. Since the engine was rebuilt for excessive oil consumption, it suddenly became obvious that the honeycomb converter element in the exhaust manifold was plugged up so tight with coked oil the exhaust gas couldn't get out the normal way! By removing a spark plug, the exhaust had somewhere else to go. When we loosened the manifold bolts about 1/4", the engine ran with all the plugs installed.
Since Lincoln County Tennessee doesn't have mandatory exhaust emissions testing, a hammer and a big screwdriver took care of the plugged-up manifold! Problem solved!
Jerry
