What is the correct amount of torque for a spark plug on a GM (Chevy) 3800 engine. The shop 200 Impala/Monte Carlo shop manual contains a discrepancy.

On page # 6-408. under Exhaust Manifold Installation (left) the manual says to tighten the spark plugs to 27 N-m or 20 lb ft. The same can be said for the torque specification for the right side (page 6-412.)

On page #6-547-548, under Spark Plug Replacement, the manual indicates to tighten the spark plugs to 15 N-m or 11 lb ft (page 6-548.)

Am I missing something here?

What is the proper tightness or torque for a spark plug on a GM 3800 (Chevy) engine - 11 ft lbs or 20 ft lbs?

Thanks in advance for your reply(s),

Bill