can anyone help with exhaust and intake manifold date codes ( and what the numbers mean on these items) and where i can find them? thanks john
A=JANUARY B=FEB C=MARCH D=APRIL E=MAY F=JUNE G=JULY H=AUGUST I=NOT USED AS CAN BE CONFUSED FOR #1 J=SEPT K=OCT L=NOV M=DEC These numbers will be followed by day of month. example B15=February 15 These same date codes are used for intake manifolds, heads and engine block. They all should be pretty close same month and close days but not exact. The engine block date code is located on the front of the block near the timing cover in 70 through mid 71. Late 71 code is inside block near lifters. I think exhausts have three digit Julian date. example 321=321'st day of year. Not 100% sure on this as I have exhaust manifolds with all kinds of crazy numbers and clocks on them. Duane may no better on these.
Intake date code is found right in the front of the intake near firing order and part #. Very visible. Easiest date code to find on car.
Thanks for the plug Marco & Jim, here is the info. Duane Date Code Manual I have just finished a new reference book about date coding systems for mid 60s thru early 70s GM cars. Below is an excerpt from the book that explains what it covers. Mission Statement As the interest in vehicles with original or correct components continues to climb, the ability to verify these pieces becomes more and more critical. Most parts, including major drive train components, not only have part numbers stamped or cast into them, but are also date coded. Therefore, an understanding of both part numbers and date codes is needed to verify the correctness of these parts for any given vehicle. The goal of this Manual is to familiarize the buyer with the various date coding systems used throughout these vehicles. The hope is that this knowledge, combined with a familiarity of part numbers, will give the buyer the ability to accurately determine which parts are correct or incorrect for vehicles built during these years. Four major items will be included within this manual; 1. There will be a discussion regarding the Fisher Body ID Plate, which is the key to understanding the correctness of all date coded parts on a vehicle. 2. There will be photographic examples of each type of date coding system, whether it is cast, incise stamped, ink/paint stamped, or is printed on a tag, and an explanation of how to decode them. (The only exceptions to this will be with the Glass Codes. Due to the difficulty of photographing them, drawings will be used instead of photos.) 3. Calendars for the years 1964 thru 1972 will be included, listing the day of the month, day of the year, and week of the year, plus a guide explaining their use. 4. And finally, at the end of this manual, will be a comprehensive list of parts that will reference the types of date codes commonly found on them, and when necessary, the approximate locations where these codes can be found. This book will decode Buick, Chevrolet, Oldsmobile and Pontiac date coded parts including; body panels, front end sheet metal, radiator core supports, all makes of glass (LOF, PPG, & DCL), DMI sport mirrors, radiators, all major cast engine components, vacuum trees, oil sending units (at least for the gauge equipped cars), water pumps, valve covers, oil pans, both varieties of clutch fans, Rochester, Holly, & Carter carburetors, starters, distributors, alternators, air cleaners, AC compressors, AC hoses, voltage regulators, steering boxes, master cylinders, power boosters, brake drums, calipers, brake rotors, car frames, front suspension center links, seat belts, radios, seat frames, bucket seat headrests, steering columns, Turbo-Hydramatic auto transmissions, Borg Warner T-10 and Muncie 4-speeds, Ford top-loader and Saginaw 3-speeds, rear axles, rims/wheels, spark plug wires, and probably a hundred other parts I haven't mentioned. (Please note; production codes for engines and transmissions will not be discussed.) The cost of the book shipped is $44.50. This includes $40.00 for the book, and $4.50 for shipping anywhere in the continental US. If you are interested in purchasing this book, you can send a check or money order to, Classic Car Interiors 120 President Ave. Rutledge, Pa. 19070. Thank you for your time. Duane
John, There is an order blank for Duane's book on www.atlantabuick.com it has all the info you need to acquire a copy. Its listed under the "General Motors Date Coding" section. :TU:
