ECL Codes, why so much confusion?

[hubleyman]

Since I'm in such a gabby mood (sorry guys), it's time for me to touch base on ECL (Exception Control Letter) Codes.....

There seems to be a great deal of confusion about them out there in "Forum" land.

Correct me if I'm wrong, but I believe ECL codes are simply variations related to a particular option. That's it. No big mystery. Now trying to find the correct ECL code for a certain combination of parts could be a BIG challenge if you don't have enough "real" examples!!!

Typically it is a builder code to indicate some specific details related to assembling a car with that particular option and as it effects other option combinations too.

As an example, a console equipped four speed shifter vehicle might need a different shift boot and trim ring as compared to a non-console 4 speed car. Bench seat versus buckets - different shifter handles? Other options can also effect the assembly (brackets, wire harnesses, punchouts in sheetmetal or interior panels, etc.). So the ECL code for one trany combination might possibly be an AD while an AG could possibly indicate another with a minor difference.

While reading an exciting recent L78/M40 Camaro "discussion", I noticed others trying to figure out why the transmission ECL code would be different for a higher horsepower engine equipped with the M40 trans. There definitely is differences in the actual transmission (components, shift points, etc.) but I believe that would be covered by the final assembly code on the actual trany. The difference in the actual car assembly might be as simple as the bracket that supports the kickdown switch. A low horse engine Q-jet carb kickdown switch mounting bracket versus a high horse engine with a Holley kickdown switch mounting bracket. One basic variation could be a different ECL.

Being a Midyear Corvette enthusiast, I've used ECL codes from trim tags for years to help determine factory installed interior and trim options or variations. Each combination of options creates a different assembly code. Hardtop or not, headrest seats or standard, etc. A car with power windows is different than those equipped with manual windows because they need to punch out the console for the power window switch, and not punch out the door panels for the manual window cranks. Order the AM/FM radio in '65? There are 16 different ECL codes for that radio: With or without side exhaust?? Base or higher HP engine. W or W/O A/C. All different ECL's to show which radio suppresion ground straps to use, or which holes to punch... Is the radio any different....no... but the variations or options to go with it are.

It has also been mentioned that the ECL's might relate to the price increases for certain options during the year. While anything is possible, the "blueprints" for building the car probably don't have anything to do with the pricing. My guess is the ECL codes are assigned long before the vehicle is built and before the final pricing (which is determined when the vehicle actually is built) gets applied. But that's just my opinion......

So there, now it's time to relax with a nice glass of Wine. Thanks for laboring through my ramblings.... Charlie

[Jeff H]

ECL codes do change based on combination and also based on prices/combinations. Just look at Jerry M's book on the 5 different versions of the 69 Z28 option during the year. The M21 codes vary for different reasons and the M40 codes vary for completely different reasons. Assuming you understand them is a bad assumption. M40 merely refers to turbo hydramatic transmission and the base engines got the TH350 and the high hp engines got the TH400 but they were both noted as M40 so the ECL makes a big difference. The codes vary from year to year and model to model so you can't even try to compare Corvette codes to Camaro, Nova or Chevelle codes. We're all trying to learn more about how GM built these cars and these invoices with the ECL codes will help us learn a lot more than we currently know. I think you completely misread the posts about it but if you know the different M40 ECL codes for 1970 then please share with us.

[YENKO DEUCE REGISTRY]

I thought the window codes for a TH350 would be M38 vs. using M40 as a generic indicator

[Jeff H]

[ QUOTE ]
I thought the window codes for a TH350 would be M38 vs. using M40 as a generic indicator

[/ QUOTE ]

That's what I thought as well. But remember, on the ordering sheet, the 4 speed was simply listed as a close ratio or wide ratio and not M20 vs M21 or M22. So the generic order would be for the turbo hydramatic transmission, not actually specifying the TH350 vs TH400. The paperwork Ed has is great and goes along with Jerry M's paperwork to help validate combinations and codes.

[YENKO DEUCE REGISTRY]

Why would the window stickers call out the individual 4 speed versions (M20, M21 & M22) but not the individual auto's?