Take off the valve cover and roll the engine with a wrench to Top Dead Center (TDC). Then you should see a mark on the thrust washer of the cam. The mark should be starting to line up with the line on the cam tower. Roll the engine in a clockwise rotation untill the lines are perfectly in line. Read the degrees on the crank. More than 4 or 5 and you have too much chain stretch. If you are doing this type of work, plan on the rails and tensioning rail too.
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