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The updated procedure found attached here: https://wiki.bentleypublishers.com/download/attachments/25952263/P989_102.p.28-29.correction.pdf describes temporarily installing the camshaft cases prior to tightening down the cylinder head nuts. If the head bolts are tightened without first fitting the cam cases, the cam cases may not perfectly fit the alignment pins on the cylinder heads. Temporarily installing the camshaft cases insures the cases will fit once the heads bolts are torqued.
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