ACTION
Clarify the design changes and provide a detailed interchangeability guide between the 2003-2007 model years. Identify correct part combinations required for proper engine function.
CYLINDER HEAD IDENTIFICATION
A pre-commonized engine has an engine serial number from 6,000,000 to 6,723,721 (Indianapolis built engines have 7 digits beginning with 6) or 1 to 299,092 (Huntsville engines). The cylinder head, head gasket, head dowels, injector hold down clamps, rocker arm carrier, and rocker arm carrier mounting bolts differ between the “pre-commonized” engine and the commonized engine.
The commonized engine head dowels are 20 mm straight dowels. Previously released service kits allowed the use of a commonized head on a pre-commonized engine. If a pre-commonized engine has a commonized head installed, the head dowels will be 18 mm to 20 mm step dowels. You must take additional steps to determine the correct head kit to use for repair.
NOTE: TO PREVENT ENGINE DAMAGE, IF SERVICING BOTH ENGINE BANKS ON A PRE-COMMONIZED ENGINE, DO NOT MIX CYLINDER HEAD PARTS BETWEEN LEFT AND RIGHT BANKS. IF PREVIOUSLY REPAIRED, THE ENGINE MAY HAVE TWO DIFFERENT CYLINDER HEADS.
Check the injector hold down bolts and rocker arm carrier mounting bolts. If the injector hold down bolts are T40 and the rocker arm carrier mounting bolts are M8, repair the engine using the remanufactured pre-commonized head kit. Replace the step dowels with 18 mm straight dowels.
NOTE: THE VERSION OF COMMONIZED HEAD INSTALLED ON THIS ENGINE MATES WITH THE PRE-COMMONIZED INJECTOR HOLD DOWN CLAMPS AND ROCKER ARM CARRIER.
Once the repair is complete, the engine will be returned to its original configuration. If the injector hold down bolts are T45 and the rocker arm carrier mounting bolts are M10, repair the engine using the commonized head kit.
NOTE: THIS ENGINE HAS BEEN CONVERTED TO A FULL COMMONIZED HEAD CONFIGURATION, INCLUDING COMMONIZED ROCKER ARM CARRIER AND REVISED INJECTOR HOLD DOWN CLAMPS. THE COMMONIZED ROCKER ARM CARRIER AND REVISED INJECTOR HOLD DOWN CLAMPS MUST NOT BE USED WITH A PRE-COMMONIZED HEAD.
