Usage:
All 3304 And 3306 Engines
Description of Change: Improved cylinder heads and valve covers are used on the above engines. The improved cylinder heads provide more mounting space for the air inlet pipes. The improved cylinder heads no longer have clearance for the valve cover lip at the two air inlet pipe pads. Because of the changes to the cylinder heads, either a new valve cover must be used or the former one must be modified.
Adaptable As: The improved cylinder heads are direct replacements for the former cylinder heads. The part numbers for the cylinder heads did not change.
When an improved cylinder head is used, it will be necessary to use either a new valve cover as shown in the chart, or modify the former valve cover. The lip on the former valve cover must be removed between points A and B as shown in the illustration to allow the valve cover to seal correctly on the cylinder head. Remove 2.5 mm (.10") of the lip from the valve cover. Put a 15.8 mm (.62") radius (four locations) at each end where the lip of the valve cover was removed. Make sure there are no sharp edges and that the valve cover is thoroughly cleaned after the valve cover is modified.
Dimensions for modification to former valve cover.