The Supercar Registry - COPO Chevelle trim tag data

Tom,

This may help clarify things. I just recently re read the Nova Times series from several months in late 1993 on the Fisher body side of the Willow Run Plant. Several Willow Run key employees were interviewed. It ran through the build sequence in generic detail covering the many years Novas were built. It a generic sense it might help this thread since GM probably did similar things since the build sheets, trim tags, VIN plates are similar between Chevy's. In a few words here are the highlights. (This summary does not do the series justice! Forgive me if I am a little too basic here and by all means pick it a part! [img]/ubbthreads/images/icons/tongue.gif[/img] )

Body flow was controlled by the SEQUENCE (my emphasis) number based on the Production Schedule generated by the Data Processing (computer) department and published days in advance of the day the body was started. This controlled the "Body Shop Order of Run" which determined how many of each body type was put on the line and in what SEQUENCE. Body styles and options were distributed so as to not have 20 AC cars in row. It took longer to install AC than just a heater. The amount of time to install all of the options was determined by the speed of the line. Options were spread through out the production schedule to keep the line moving. Color was also a concern. The Body Shop Order of Run list creates a SEQUENCE number. As the body starts down the line the operator took a floor pan and marked a 4 digit SEQUENCE number in crayon from his copy of the "Body Shop Order of Run" onto it . Later as the body moved down the line a Fisher Body build sheet matching the crayon number was taped to the body. The sheet listed body style and options needing different body parts.

Until now the crayon number identified the body. If the Fisher Build sheet was lost, the crayon number ruled. As the completed body reached the Scheduling Clerk's Station the clerk checked the crayon number against the build manifest. The clerk matched the number to the last 4 digits on a trim tag which was already stamped with the BODY number. The clerk would then place the trim tag into the stamping machine. He added trim, paint and date codes. So the date code reflected the week the body was welded together. Since the body was not painted, the date code might be an earlier week than assembly week indicated on the VIN label.

The Scheduling Clerk was also responsible for the VIN. He took the VIN shown on the manifest and passed it to a portable stamping machine operator who dialed it into his machine. This was how the hidden VIN was stamped on the body. The VIN was probably assigned by computer, but this was not discussed in the article. So this is the missing piece of the puzzle.

The interior and exterior paint code was marked on firewall prior to painting. Willow Run BATCH painted cars. So regardless of the body number all red cars were pulled aside waiting their turn at the paint booth. At this point the body SEQUENCE number of the trim tag no longer mattered. As bodies moved through the rest of Fisher Body there we assigned a NEW SEQUENCE number at various stages. That is why the SEQ number on the Fisher Body sheet does not match BODY number or VIN. A body might have many SEQ numbers during the build process. A new SEQ was assigned by GM after the body passed thought the wall.

The function of the BODY number was only the original SEQUENCE number for the body. Since COPO cars were all built the same, Data Processing (the computer) probably distributed them though the Production Schedule. Having ALL of the COPO cars in a row probably did not happen. If a part was not available and the computer knew it, the body would not be scheduled to be built. If a shortage was found on the line the body would be pulled off. Pulling a body of the line was very bad.

Cars moved through the plant like ants at a picnic. SEQUENCE number was used to control the flow not VIN or Body Number. This explains why neither VIN nor Body Numbers are in date sequence.

Greg (sorry for the length. The fewer words I used the longer the message. [img]/ubbthreads/images/icons/grin.gif[/img]