1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

[Richard M.]

1956 to 1962 ECL Querry:
Asking for help trying to decipher RPO and ECL (Exception Control Letter) single letter codes for Chevrolets built before 1963. I've come across some data for some early Chevrolets and I see single character ECL's and would like to learn what they mean.

E.G. A B C D E F G M N V W ....etc

I think "A" or "B" is likely "BASE" for either: A Coupe or B Convertible. But I'm lost after that.

Also, some are 2 letter codes, like XB XC XD XE etc. I'm thinking the X? codes include C60 for Pass cars and Trucks as obviously no pre 1963 Corvettes had C60 Air Conditioning, and this ECL system probably carried over for 1963 Corvettes. I see reference to these 2 letter codes back to 1956 Pass car production, which appears to have carried over to 1963, but then went away in 1964.

If any of you folks were there at Chevrolet in the 50's and early 60's and have some insight into the ECL codes Chevrolet used then, it would be greatly appreciated.


RPO 565 Querry:
Also, trying to gain knowledge regarding RPO 565 "Body Equipment" available from 1957 to 1961. Does anyone know what this RPO consisted of? A friend of mine had some notations on his 1959 Corvette, with "565" painted on his front crossmember. We think it's RPO 565, but trying to understand what the RPO is. It shows up in the 1959 AIM RPO page as "RPO 565 Body Service List", but on no other AIM from 1956 to 1958 nor 1960 to 1962.

We have also seen RPO 565 referenced on other Chevrolet documentation, like the 1960 Corvette AMA spec in the FOA/RPO details page. There it states:

" Body Equipment (Service)* " with a notation...... " * - Includes Hardtop , when used. "


MC & HNY

Rich

[David B.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

RPO 565 is listed as an option specifically for the Corvette. The production quantity was very low. '57 - 5, '58 - 0, '59 -1, '60 - 3, '61 - 1, and '62 not listed.The GM production quantity Alphabetical Index - Chevrolet Passenger RPO's FOA's lists this option under the index heading BODY. 2 other options are also listed , RPO 347 & RPO 669 both of these options are specifically for passenger car production and are listed as: Deluxe Body Equipment. RPO 347 for passenger cars and RPO 669 for Corvair. I suspect RPO 565 has erroniously never been listed in Corvette option production because no one is really sure what it entails. In an article submitted to The Restorer (not yet published) revising 56-57 option quantities I have listed RPO 565 in the 57 production quantities and took a stab at referring to this option as 270HP Corvettes equipped with RPO 684 HD brakes & suspension. As for the single character letters A B C -- etc. for the years before 1963 the RPO Production quantities that list these numbers are not consistant with there use. In other words the letter A for instance in one RPO listing does not necessarily mean the same for another RPO listing. The letters can be interpretted if one has access to other GM production documents.

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Thanks for your reply David. I was hoping for information from someone as knowledgeable as you.

My friend's car with the "565" identifier on the front crossmember appears to be originally a low HP car as the tach has the low redline and is dated right near the car build date. Interestingly, it appears he has that ONE and Only 1959 with RPO 565. There was a article in Vette Views a few years ago about RPO 565 where he co-authored the story with another enthusiast. I'll see if I can get a copy.

Also, his car has some interesting Trim features. He's not sure if it was done at St Louis as part of 565, or by a prior owner years ago. So then we were wondering if RPO 565 may have varied based on "Instruction" notes during build, year, model, color, trim, RPO combinations, etc. Meaning some cars had different features modified based on what its options were.

Another thing we found was reference in some AMA specs as mentioned, along with some info regarding the Passenger car/Truck "Body Equipment" options, where "undercoating" was mentioned. Then we wondered if his car simply had undercoating applied on the complete underbody on his car. Evidence not obvious though.

What's really confusing is that 565 was supplied on some years and not others, and ONLY is listed in the 1958 AIM, no other C1 AIM that I am aware of.

Rich

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Here's the article, also pdf attached below, and the photos of the crossmember.

[David B.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Rich,
GM documentation referred to in my possession clearly lists RPO 565 as a Corvette option. Being listed as Body Equipment in 1957 the production quantity indicates that 5 Corvettes were produced with this option. No further explanation is given. In reading Ken Kayser's Vette Vues article (I have a high regard for Ken) I found his explanation for 565 in the 1957 production line a real hard "chunk" to swallow, also your idea of undercoating equally "unappetizing". I think your mentioning of unusual trim items might be a possible answer. What are (were) they?

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Rich,
GM documentation referred to in my possession clearly lists RPO 565 as a Corvette option. Being listed as Body Equipment in 1957 the production quantity indicates that 5 Corvettes were produced with this option. No further explanation is given. In reading Ken Kayser's Vette Vues article (I have a high regard for Ken) I found his explanation for 565 in the 1957 production line a real hard "chunk" to swallow, also your idea of undercoating equally "unappetizing". I think your mentioning of unusual trim items might be a possible answer. What are (were) they?

David,

I guess because I've seen so many references with varying explanations in the GM docs, it's confusing to come up with a definite answer. Some docs lead one to believe it's trim, another it's under the body, another engine related. As far as Ken's analysis, I'm unaware how he came to that possibility.

As far as mine regarding the undercoating, the 1958 Corvette AMA Spec clearly defines RPO 565 as "Underbody Equipment".See below) Maybe it's a WAG, but I suppose it's possible. I'M not sure about the trim possibility.

[David B.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

In tabulating all 57 Corvette option quantities I found numerous discrepancies from what has been published as fact for many years. One of those discrepancies involved RPO 684 which historically has been recorded as having 51 57 Corvettes so equipped. Confidential GM production quantities list only 48 Corvettes as being equipped with RPO 684. It further confirms that 43 RPO 579E Corvettes (air box) were produced. A number that is accepted as fact. It is also commonly accepted that a number of 270HP 57 Corvettes were built with the RPO 684 option. While it might be a little bit of a stretch, the option number 565 seems to fall in between the engine code designations RPO 469 thru 579. Since there never has been a quantity designation given for 270HP RPO 684 equipped Corvettes it seemed logical to me that the RPO 565 option might the quantity number difference between 43 air box cars and 48 RPO 684 equipped Corvettes. Obviously the 270HP cars would not utilize the air box which would than require some inner body modification to install the HD brake duct work. Your friend,s 59 being a low HP car does seem to contradict what I have just stated but it would require more info to reach a better conclusion.

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

David, I agree. Published prior data(Spec Guide, Noland's book, etc) says 43 RPO 579 "Airbox" cars and 51 RPO 684 HD Brake/Susp cars, which include the 43 Airbox cars, which would lead one to believe there were 8 RPO 684 cars without FI, i.e. with RPO 469C(2x4BC).

But A friend showed me some GM RPO data that conflicts with these numbers. It states 48 RPO 684 cars also. That would leave 5 BigBrake cars without FI. Most likely, they would be the 270HP Duntov Cam cars. I too doubt they'd be base engine Powerglides. I see that because there were 5 1957's built with RPO 565 becomes a thought now too. Coincidence?... Maybe. Factual?... I think more data could help.

....Something just hit me while writing this. In looking at the 1953-1967 Spec Guide, I always wondered where the suffix letters came from, shown for RPO's 469, 470, and 579. A,B,C E,F...... THOSE are the single letter ECL's, are they not? How did the Spec Guide Author(s) and Noland in his C1 book decipher those? I'm eager to know. Maybe they had some cross reference list. This is the primary reason I posted..... What these suffixes represent.

Your assessment of the 48 RPO 684(HD Brake/Susp) cars minus the 43 RPO 579(Airbox/FI) leaving 5 possible RPO 469C(2x4BC) cars now makes much more sense to me. However, I tend to think that those 5 wouldn't have any special "Body Equipment" due to the BigBrake option. Wouldn't they just follow the RPO 684 AIM instructions to build them? That clearly shows the body modifications for ductwork, etc, right?

Coincidentally, I recently looked at a 1957 RPO 684 "long time stored" car. It's NOM so no engine data to help. I'll have to also freshen up my 1957 skills....Did the Duntov Cam cars use a dash mounted High RPM tach? I've learned a little bit about the Airbox cars and know they used the column mounted tach. I'll have to look and also look really close at the front crossmember to see if any evidence of orange painted numbers are there. That'd be quite interesting. I'm going to be in the area of the car tomorrow.

Rich
edit....PS You may want to send a Email or PM to Rich Mauser,

https://www.forums.ncrs.org/member.p...Mauser-(27974)

who owns the '59 with the 1-of-1 RPO 565 to get more details about his car.

[Jim L.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

This discussion of the RPO 565 is interesting but you two are not recognizing one fact about the '57 RPO 684 cars: The absence of the air box equipment does NOT automatically mean the presence of a dual quad engine.

The first RPO 684 car delivered to the west coast is fuel injected but does not have an air box. This is the car initially raced by Jerry Austin and later owned by Bob Bondurant. The present owner has had the car since 1962. There may (or may not) be others like it but there is no question that this car is the Real Deal.

Jim

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

This discussion of the RPO 565 is interesting but you two are not recognizing one fact about the '57 RPO 684 cars: The absence of the air box equipment does NOT automatically mean the presence of a dual quad engine.

The first RPO 684 car delivered to the west coast is fuel injected but does not have an air box. This is the car initially raced by Jerry Austin and later owned by Bob Bondurant. The present owner has had the car since 1962. There may (or may not) be others like it but there is no question that this car is the Real Deal.

Jim

Jim, David used the word might (be) in post#7 about that, and I was merely recognizing that it might be a possibility too but needs further data to confirm. I can only speculate right now, but it certainly would be fun to get this RPO 565 mystery solved.

I also discovered yesterday that the 1961 AIM shows RPO 565 in the RPO Index, listed as "Body Service List". It has a "#" notation which says "Index Only" and to "(SEE INTRODUCTION SHEET)" for info, but I see nothing there helps define it. In 1961 1 car had RPO 565.



Rich

[David B.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

This discussion of the RPO 565 is interesting but you two are not recognizing one fact about the '57 RPO 684 cars: The absence of the air box equipment does NOT automatically mean the presence of a dual quad engine.

The first RPO 684 car delivered to the west coast is fuel injected but does not have an air box. This is the car initially raced by Jerry Austin and later owned by Bob Bondurant. The present owner has had the car since 1962. There may (or may not) be others like it but there is no question that this car is the Real Deal.

Jim

The car you mentioned not having the air box would therefore not be one of the 43 optioned 579E 57 Corvettes. However, being equipped with RPO 684 it would require the inner fender modification for the HD brake duct work which could fall under the category of body modification. This would still leave 5 RPO 565 57 Corvettes.

[Richard M.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Gents, My thoughts. Please keep in mind I'm in research mode only, eager to learn, never owned a 57, let alone a BB/HDsusp/FI car, and only saw ONE real BB/HD/Airbox car in my lifetime at the Charlotte Nationals in 2010. The owner saw me walking by as he was leaving his stunning black car and noticed my eyes lit up like a firecracker. He graciously turned around and asked me if I knew what it was. I immediately told him I kinda knew it was probably a BB/HDsusp car when I saw the Elepahant Ears up front, and it was a fuelie as it had the FI emblems on the coves, but the hood was closed. I asked....."Airbox?". He said yup, opened the hood, IIRC a little pee came out and he then gave me the full tour. I took many photos(see below). A true gentleman......Irwin Kroiz.

Sorry for the detour.....

This discussion of the RPO 565 is interesting but you two are not recognizing one fact about the '57 RPO 684 cars: The absence of the air box equipment does NOT automatically mean the presence of a dual quad engine.

The first RPO 684 car delivered to the west coast is fuel injected but does not have an air box. This is the car initially raced by Jerry Austin and later owned by Bob Bondurant. The present owner has had the car since 1962. There may (or may not) be others like it but there is no question that this car is the Real Deal.

Jim

Jim, I understand better now and fully agree. Since GM Data(per David's info) lists 48 RPO 684 1957 Corvettes, not 51 as previously thought, and 43 of those 48 were RPO579E Airbox cars, and GM Data/Spec Guide states there were 713 of RPO579B FI/HL Cam 283HP, then that West Coast car is therefore one of 5 remaining non-Airbox RPO579B/RPO684 FI cars. If it didn't have RPO684 it would have been 1 of 713 cars. With this, it appears to me that the total of 5 remaining RPO684 non-Airbox cars were not ALL 270HP cars, merely because the math doesn't work. Some maybe, yes, but not all 5.

The car you mentioned not having the air box would therefore not be one of the 43 optioned 579E 57 Corvettes. However, being equipped with RPO 684 it would require the inner fender modification for the HD brake duct work which could fall under the category of body modification. This would still leave 5 RPO 565 57 Corvettes.

David, I have to think that RPO565 is not involved with RPO684 assembly and body modification. Every skirt hole, screw hole, and additional part for the HD brake RPO is clearly defined in the RPO684 AIM section. Also, the 1957 AIM does not even list the RPO 565 in the RPO Index. Could it be involved? I'm still open to any possibility at this point, but I still believe we need more data.

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My trip to visit that RPO684 '57 scheduled for today has been delayed until tomorrow.

Rich

[Jim L.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

Rich, the configuration of the fresh air hose on the driver's side as depicted in your RPO 684 AIM sheets is exactly as the Austin/Bondurant '57 is built.

[Loren L.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

I believe that another RPO 684 non-airbox car was delivered to Rosenthal Chevrolet for Bark Henry; in that case, the airbox was added later when available. Car is now owned by John Neas of Tulsa.

[David B.]

Re: 1956 to 1962 Chevrolet and/or Corvette RPO Single Letter ECL Codes & RPO 565

No problem with the existence of non air box 57 Corvettes either FI or 270HP equipped with RPO 684. In fact the 2 production Corvettes at Sebring in '57 had the air box removed after testing showed they ran better without them. Hence, the double air cleaners. No problem with the AIM showing how to install the ducting without the air box. But the fact is only 5 non air box Corvettes either FI or 270HP were built in 1957 with RPO 684. Call it coincidence but the GM records show 5 RPO 565 Corvettes being built. These two options may turn out to be totally unrelated but the coincidence seems to fit an explanation for 565, at least for 1957.