I looked through our service manual, site sources and researched myself and cannot find torque specifications for the engine. The best thing you can do is to match the thread pitch, grade and size to an online torque chart for hardware. Hardware has it's own torque specification but keep in mind that the engine torque may be different as the torque specifications for the bolts themseelves is the safe level and not the requirement that the engine may need for proper seating of parts.
Sorry we don't have the information as Opel info is mostly from Europe and our resources our minimal at best for that vehicle.
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Tuesday, March 6th, 2012 AT 3:54 AM