Subject: V-8 Distributor Chart
Model and Year: 1955 Thru 57 Passenger Cars and Trucks
Source: Chevrolet Service Bulletin
Bulletin Number: DR #291, Section VIy, April 26, 1957
TO: ALL CHEVROLET DEALERS
Chart on page 2 of this bulletin lists V-8 Distributors used on 1955 thru 57 Passenger Cars and Trucks with spark setting @ idle.
The numbers stamped on the distributor plates are used as a means of identification only. In some instances the service number and numbers on plats are identical.
Numbers on plats should not be used as a basis for ordering service parts.
Spark Setting
To eliminate confusion all spark settings are now to be made at idle only.
Markings on the ignition timing tab attached to the front end cover are in 2 degree increments from the "0" marking.
In heavy duty truck operations, where spark plug burning and pre-ignition are problems, remove the vacuum spark advance.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
© Copyright General Motors Corporation. All Rights Reserved.
Article ID: 780
Created: August 3, 2014
Last Updated: August 3, 2014
Author: Rob Loszewski
Online URL: https://www.corvetteactioncenter.com/tech/knowledgebase/article.php?id=780