1955 Corvette: Service Bulletin: Ignition Timing
Subject: Ignition Timing
Model and Year: 1955 6 & V-8 Engines
Source: Chevrolet Technical Service Bulletin
Bulletin No: DR - 190
Date: December 13, 1954
TO: ALL CHEVROLET DEALERS
An alternate method of setting ignition timing on 1955 6 and V-8 Engines may be used in the Field to obtain more consistent results at idle.
Disconnect the Vacuum Spark Advance Unit and set spark of #1 cylinder at 5° BUDC at 1000 RPM.
Disconnect the Vacuum Spark Advance Unit and set spark #1 cylinder at 8° BUDC at 1000 RPM.
The present Shop Manual method of setting at idle may be used even though the 1000 RPM method is preferred. In either case, ignition timing may be advanced or retarded to obtain acceptable detonation and performance.