• About ECLs
• Paint code ECLs
• Trim Code ECLs
• Example Cowl Plates
• Acknowledgements

About ECLs

ECLs were used by Chevrolet to specify a particular configuration of a RPO. They were the basis for ordering parts from suppliers and informing the assembly line of exactly which parts were needed for each vehicle. When assembly of a vehicle commenced, line workers needed to know which parts were required and that all the required parts would be available. The accountants needed to know the costs. Generating complete parts lists for each vehicle model in its standard, or base, configuration was relatively straight forward, but tracking the parts and costs for RPOs was a far more complicated matter. RPOs frequently had different configurations when installed on different models. For example, the Custom Equipment package for R1205/44/54 was quite different than for the Greenbrier. Additionally, when different RPOs were ordered together, their parts lists might need to be modified with additions, deletions or substitutions, such as when Custom Chrome (RPO 393/V37) and Wheel Covers (RPO 132/P01) were combined and the chrome hubcaps were deleted from RPO 393/V37. Interactions between options are not always obvious: RPO 123/U60 (Radio) differed for vehicles with standard and automatic transmissions because different accessory wiring harnesses were needed. The myriad interactions between RPOs created many different installation configurations - in both 1962 and 1963 there were 27 different configurations just for RPO 123 (direct air heater). Tracking the specific parts required for all of the different RPO configurations, and their costs, was a potential bookkeeping nightmare.

The solution was the Exception Control Letter (ECL) system: for every possible RPO configuration the Engineers created a separate parts list and assigned a unique ECL. With the appropriate ECLs appended to the RPOs, the plant could identify all the parts needed for assembly of each vehicle. When construction commenced, the vehicle was built according to the RPO codes on a Broadcast Sheet that accompanied the vehicle down the line. Documents called Exception Control Letter Sheets showed how different RPOs were configured for each ECL, and Engineering Parts Lists identified everything needed for each configuration. Not uncommonly, RPO configurations changed during a production year, necessitating corresponding changes to the ECLs, and further complicating the task of deciphering the ECLs today.

The paint color RPOs for Corvair 95s ran in a 7xx series in 1961, but in a 5xx series from 1962 on. Each color had a separate RPO for application as a solid (monotone) exterior or two-tone, such as, Cardinal Red solid (714/514) and two-tone (740/544), and Brigade Blue solid (507/707) and two-tone (537/736). The main body color was known as the primary color, while the stripe applied in two-tone jobs was called the secondary color. There were two white colors used on FCs. “Pure White” comprised RPOs 721/521 (solid) and 545(two-tone). “CameoWhite”, given RPOs 726/526 (solid) and 747/541 (two-tone), was sometimes referred to as “Off White”. For two-tone vehicles where the primary color was either of the two whites, the secondary color was Cardinal Red. For all other two-tone jobs, the secondary color was Cameo White.

Paint code ECLs were single letters in 1961-63. Available documents and with agreement of registry data indicate that all solid color RPOs carried an ECL of "A", whereas the ECLs for two-tone RPOs were "E" for the Corvan, "F" for Greenbrier, and "G" for pickups. The different codes reflected that two-tone painting was more expensive than applying a solid color, and the process of two-toning a pickup was different and more expensive than for a van. The 1963 Price Information supplement also lists the ECLs "M", "N" and "V - X" for Rampsides, and "H - L" and "P -V" for R1205/06. It seems probable that these additional codes were intended for vehicles with RPOs 521 and 545 (as described below) although no examples have yet been found on cowl plates.

In 1964, Chevrolet endeavored to unify the paint ECLs using two letter codes. For most two-tone paint RPOs, "AA" was appended for R1205, "AB" for R1206 models, and "AC" for Rampsides and Loadsides. The exceptions were RPO 545 (see below) and some R1206 two-tone RPOs that carried the “AA” ECL.

The ECL system for Pure White FCs was different and more complicated than for the other colors. Most likely, RPO 521/545 were handled differently because Pure White needed to be substituted for Cameo White on other painted features, such as mirrors, bumpers and the hubcaps (see more below).

The 1963 Price Information supplement gives the RPO 545 ECLs as "E, F, H - L" & "P - U" for R1206/05, and "G, M, N, V - X" for R1254. However, only the ECLs "E, F & G" (as in 1961-62) have been observed among vehicles in the registry. The corresponding page in the 1963 Price Information supplement is dated 3/18/63, and the additional ECLs may have been introduced late in the production year. Registry data reveal that RPO 521 also had special ECLs, which seem to apply to all models. So far, only the ECLs "A", "B" and "F" have been found among 1963 FCs, and "C - E" are speculated to have been used.

The Price Information supplement for 1964 shows the RPO 545 ECLs "AA - AF" and "BB - BF" for R1205/06 and "CA - CF" for Rampsides, and some of these ECLs have been observed among registry vehicles. Again, Registry data for 1964 - 65 FCs show distinctive ECLs for RPO 521, which, as in 1963, appear to apply to all R10 models. The RPO 521 ECLs "AB", "BA", "BB", "CA" and "DA") have been observed among vehicles in the registry, and the RPO 521 ECL "CB" is speculated to occur.

It is not currently known which configurations are associated with the RPO 521 and 545 ECLs, but quite likely they involved substituting Pure White for Cameo White on other painted exterior features, such as bumpers and the hubcaps. The Custom Chrome (V37) and Custom Equipment (Z60) options substituted chrome bumpers and hubcaps, and RPO V37 specified wheel covers instead of hubcaps. Since in some vehicles chrome bumpers and wheel covers replaced the standard painted ones, different painting requirements were required.

The 'trim code' identified the configuration of interior features of the vehicle. The base or standard, configuration was identified with a trim code of 'STD', and within each model, the standard configuration was a gray (1961) or fawn (1962-65) interior paint scheme. When the vehicle was ordered as a 'Deluxe' the trim code included the Custom Equipment RPO 431 (1961-62) or Z60 (1963-65). For vehicles assembled in St Louis, Z60 was preceded by the number '5', referring to the factory book detailing the different RPO configurations. The Custom Features RPO was typically followed by one or two Exception Control Letters (ECLs), which identified the specific configuration of Z60 in the vehicle. This table presents the current interpretation of how the Custom Features configurations were encoded in the ECLs.

For example, a 1962 rampside with a trim code of '431N' would have had red themed interior trim. A 1965 Greenbrier with a trim code of '5Z60KB' would have had turquoise interior panels configured for a 6-door model and rear arm rests.