03-06-04-060B: Information on New Spark Plugs and Gapping - (Jul 30, 2008)

Models: 1997-2004 Chevrolet Corvette

1998-2002 Chevrolet Camaro with 4.8L, 5.3L, 5.7L or 6.0L V-8 Engine (VINs V, P, T, Z, G, S, N, U -- RPOs LR4, LM4, LM7, L59, LS1, LS6, LQ9, LQ4)


Please disregard the Set Gap Per Vehicle Specification statement on the side of an ACDelco® Iridium Spark Plug Box. The statement will be removed from the boxes in the future.

This bulletin is being revised to add the Chevrolet SSR and the 2005 Pontiac GTO. Please discard Corporate Bulletin Number 03-06-04-060A (Section 06 -- Engine/Propulsion System).

• A new spark plug has been released for use in the above vehicles. The new spark plug has an Iridium tip instead of the current Platinum tip. Due to the different tip design, the gap of the spark plug has also changed.

The new spark plug, P/N 12571164 with AC Delco P/N 41-985, is gapped to 1.01 mm (0.040 in) when the spark plug is made.


The spark plug gap is set during manufacturing and should not be changed or damage to the spark plug may result. Any new spark plug found to not be properly gapped should not be used.

Team ZR-1
True Custom Performance Tuning