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Ignition System - Revised Spark Plug Coding Chart

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Number: 90-253-6D

Section: 6D

Date: July 1990

Corporate Bulletin No.: 016402

Subject: IGNITION SYSTEM REVISED SPARK PLUG CODING CHART

Model and Year: 1990 CORVETTE

TO: ALL CHEVROLET DEALERS

The Spark Plug Coding Chart shown in Figure 2, Page 6D4-3, in Section 6D4 "Ignition System" in the 1990 "Y" Carline Service Manual has been revised as shown in Figure 1. Please make a note of these changes for future reference.