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View Full Version : ThE ** RAREST** C.O.P.O. Car .


Z-11 396
06-23-2019, 05:07 PM
I've heard the word C.O.P.O. for a long time, but have always wondered which one of the car's is the Rarest C.O.P.O.-- Do any of you have a idea, or thought about which one it is ? How it would be picked, would it be based on the fewest cars built, the number of engines,built or the size or type of engine , or how many of C.O.P.O.s it has. >>>>>>>>>>>>

70 copo
06-23-2019, 05:14 PM
El Camino's built for U2 chase and landing gear duty??

70 copo
06-23-2019, 05:23 PM
Images:

61 vert
06-23-2019, 11:28 PM
Over 400 built with les than 10 known to survive? That's around a 2% survival number.

Lynn
06-24-2019, 01:11 AM
I've heard the word C.O.P.O. for a long time, but have always wondered which one of the car's is the Rarest C.O.P.O.-- Do any of you have a idea, or thought about which one it is ? How it would be picked, would it be based on the fewest cars built, the number of engines,built or the size or type of engine , or how many of C.O.P.O.s it has. >>>>>>>>>>>>

All acedemic as far as I am concerned. Rare does not always equal desirable.
Some guy finds a 1 of 1 special order special paint Rambler in fuscia with a chartruse interior and thinks it is worth a bundle.

COPO cars include a lot of cars other than the 427 Chevelles and Camaros (including ZL1 cars), or the 70 Yenko Duece. Most of them are not all that collectible. Odd and unusual, and sometimes great conversation pieces, but that doesn't make them desirable.

1971ls6
06-24-2019, 01:33 AM
ZL1 RS, what did they make, 2?

BCreekDave
06-24-2019, 07:06 AM
COPO ZL-1 Corvette?
At one time years ago I heard there were 2 made in 1969. Recently heard as many as 8?

firstgenaddict
06-24-2019, 07:27 AM
The RS ZL1's -specifically the original paint Lemans Blue RS ZL1 with white interior and v-roof.... there is no question.
Then down to the other special order ZL1's - IMHO you probably start with the Daytona Yellow Berger ZL1 D80- Endura car.

Keith Seymore
06-24-2019, 10:54 AM
Two door base Malibu police car in 1974 (undocumented).

As far as I know they made one.

K

70 copo
06-24-2019, 11:55 AM
Two door base Malibu police car in 1974 (undocumented).

As far as I know they made one.

K

Looked it over at GM Carlisle a couple of years ago. L-82 with steel valve covers. Undercover car!

William
06-24-2019, 12:58 PM
COPO ZL-1 Corvette?
At one time years ago I heard there were 2 made in 1969. Recently heard as many as 8?

ZL1 Corvettes were not COPOs. The engine was an RPO.

TimG
06-24-2019, 01:58 PM
I'd say the ZL1 Camaros were the most desirable COPO's built.

Tenney
06-24-2019, 02:12 PM
Blue RS ZL-1 Camaro and/or '68 Z 'vert (if that build was summoned via COPO?).

Keith Seymore
06-24-2019, 02:22 PM
Blue RS ZL-1 Camaro and/or '68 Z 'vert (if that build was summoned via COPO?).

Is that the Pete Estes car?

K

olredalert
06-24-2019, 02:27 PM
----Yes, Keith! Later to be owned by Al Maynard, who had the original paperwork stolen out of his truck at the Auburn auction never to be found. He did have copies of everything though...…...Bill S

69LM1
06-24-2019, 02:52 PM
Blue RS ZL-1 Camaro and/or '68 Z 'vert (if that build was summoned via COPO?).

Agree that this is academic, but the above statement is probably a consensus.

Personally I like the oddball stuff too, like the 70 Z28 COPO and LM1's (which are RPO's too). Neither of which bring much $$ over their "regular" models.

That 68 Z Vert has to be one of the most unusual stories ever. Back in the day when you could get anything done with the right incentive.


/R

the427king
06-24-2019, 03:48 PM
Rarest "known" differs from rarest "made". Without knowing the exact true number of copos and Zl1s made with absolute certainty, there could have always been one made that would qualify that isnt known and /or doesnt exist today .

Astock
06-24-2019, 05:53 PM
In 1998, I went out to buy a 1968 SS Chevelle. 1 owner, garage kept, low mile, orig. paint, S.Ca. car, loaded. It had Diamond pleated- puffed vinyl package tray, side panels, and a matching white 1/4 vinyl top, also puffed up. I hated it, but the widow pulled out the build sheet, and it had special instructions for all the weird stuff. There were other things, I just can't remember clearly. The original owner was a GM employee.
If she didn't have the build sheet, I would have thought it was done in TJ.

markinnaples
06-24-2019, 06:02 PM
Astock, any pictures? Sounds wild.

Astock
06-24-2019, 06:11 PM
Sorry, no.

TAR6569
06-24-2019, 06:51 PM
COPO 9801, Taxicab air conditioning for 68. Not sure of the exact specifications but production was only 255.

1971ls6
06-24-2019, 11:56 PM
Chuck you are wrong, they know exactly every ZL1 made

William
06-25-2019, 02:22 AM
L72 COPO production was buried in the Tailfins & Bowties data. The data was obtained directly from Chevrolet in the ‘80s and reprinted in the book. All of the oft-repeated ’69 Camaro production numbers-3,675 Z11s, 20,302 Z/28s-came from this data.

The data lists 1969 Camaro production by engine size; 230, 250, 327 et cetera. No 427 engine is listed but the figures total 243,085, same as 1969 production. COPO 9560 [ZL1] & 9561 [L72] build records always list L78 for some reason but not Z27 [Camaro SS].

Ergo, both COPO 427 options are included in the L78 totals.

The L48 [300/350] was the standard Camaro SS engine; 22,339 built. Camaro SS optional 396 engines; 13,659 built. Data shows 34,932 Camaro SS produced. Adding L48 and 396 totals, 22,339 + 13,659 = 35,998.

That’s 1,066 more than Camaro SS.

There were 69 COPO 9560 Camaros built; 1,066 – 69 = 997 COPO 9561 cars.

That means the L78 total of 4,889 is inflated. Actual L78 production would be 3,823.

69LM1
06-25-2019, 03:38 PM
L72 COPO production was buried in the Tailfins & Bowties data. The data was obtained directly from Chevrolet in the ‘80s and reprinted in the book. All of the oft-repeated ’69 Camaro production numbers-3,675 Z11s, 20,302 Z/28s-came from this data.

The data lists 1969 Camaro production by engine size; 230, 250, 327 et cetera. No 427 engine is listed but the figures total 243,085, same as 1969 production. COPO 9560 [ZL1] & 9561 [L72] build records always list L78 for some reason but not Z27 [Camaro SS].

Ergo, both COPO 427 options are included in the L78 totals.

The L48 [300/350] was the standard Camaro SS engine; 22,339 built. Camaro SS optional 396 engines; 13,659 built. Data shows 34,932 Camaro SS produced. Adding L48 and 396 totals, 22,339 + 13,659 = 35,998.

That’s 1,066 more than Camaro SS.

There were 69 COPO 9560 Camaros built; 1,066 – 69 = 997 COPO 9561 cars.

That means the L78 total of 4,889 is inflated. Actual L78 production would be 3,823.


Where do the L89 cars fit into that? Under the L78?

What about LM1 cars?

Just thinking out loud.

/R

William
06-25-2019, 05:26 PM
L89 was not an engine option. It was an aluminum cylinder head option that required ordering the L78 engine. Factory docs for those cars always list both. The L78 total includes the 311 L89 cars.

LM1s are not COPOs, it was an RPO. Not rare, 10,406 built in the 4 months of availability. It was odd in that it required an optional transmission; the MC1 HD 3-speed was the cheapest at $79 and was dropped as an option at the same time.

William
06-26-2019, 01:12 AM
This would be a 'rare' triple COPO. Supposedly ordered out of Courtesy Chev, Sebring, OH. The hood stripe was a single Z/28 style stripe down the center of the hood and upper grille panel.

A ZL2 SS is also known to have the COPO stripe.

69LM1
06-26-2019, 12:31 PM
L89 was not an engine option. It was an aluminum cylinder head option that required ordering the L78 engine. Factory docs for those cars always list both. The L78 total includes the 311 L89 cars.

LM1s are not COPOs, it was an RPO. Not rare, 10,406 built in the 4 months of availability. It was odd in that it required an optional transmission; the MC1 HD 3-speed was the cheapest at $79 and was dropped as an option at the same time.

I was aware that both are RPO's, I was wondering where they fit in the production numbers you gave. Ie, the L89's bundled with the L78, along with the COPO's if I understand you correctly.

The LM1' were bundled where? In the L65 (350),L48 (ss) or L30 (327)?

Just trying to follow the thought process.

Thanks,

/R

William
06-26-2019, 01:45 PM
Distinct options were tallied individually; then summed up elsewhere in the listing. There were 59,643 '69 Camaros built with 350 engines: 10,406 LM1, 22,339 L48, 26,898 L65.

Back in the day a HS bud had a new '69 Nova LM1/3-speed; another had a 383/auto/3.55 Road Runner. The Nova would put a fender on him nearly all the way down the strip. The 'runner would win but not by much. That Nova surprised more than a few people.

Charley Lillard
06-27-2019, 04:06 AM
[QUOTE=William;1452996]This would be a 'rare' triple COPO. Supposedly ordered out of Courtesy Chev, Sebring, OH. The hood stripe was a single Z/28 style stripe down the center of the hood and upper grille panel.

]
William .....does the car exist ?

Lee Stewart
06-27-2019, 05:04 AM
https://i.postimg.cc/FHwFdLv4/ttt.jpg (https://postimages.org/)

Is this what the hood stripe would have looked like?

JoeC
06-27-2019, 01:01 PM
The Tailfins & Bowties info was from Chevy computer print outs called " Passenger option production reports"

they were the production numbers given for the RPO code not for the cars built

The Fran Preve numbers were the engine codes from the Tonawanda plant not the number of cars built

The Tailfins & Bowties RPO numbers and the Fran Preve numbers come close but there are questions on the accuracy of the numbers when used to calculate the number of 427 COPO cars built.

We ran into the same thing when trying to figure out the 427 COPO Chevelle production numbers using the Tailfins & Bowties RPO numbers and the Fran Preve engine numbers

The numbers may be pretty close but I felt they were a bit high when considering all the other data

here is a pic of a page from the Tailfins & Bowties book

William
06-27-2019, 01:51 PM
"they were the production numbers given for the RPO code not for the cars built'"

Huh? Please explain.


Fran Preve wrote an article "The Numbers Game" published in the April 1987 MCR. Total Camaro L72 engine production is shown as 1,015. He states:

"Remember that these numbers indicate the number of complete engines built for production and after sale use, and do not reflect actual COPO cars produced."

He mentions an error rate of about 2% relative to actual car production. That's about 20 L72 engines. Do the math.

"...when considering all the other data..." I am confident there were 997 L72 Camaros produced.

William
06-27-2019, 02:08 PM
[QUOTE=William;1452996]This would be a 'rare' triple COPO. Supposedly ordered out of Courtesy Chev, Sebring, OH. The hood stripe was a single Z/28 style stripe down the center of the hood and upper grille panel.

]
William .....does the car exist ?

I got that WS from the original owner years ago, not very conversant otherwise. He believed it became a full-time race car and was heavily modified last he knew. I didn't get a VIN. Could still exist.

The COPO striping was just like the Z/28, extending to the leading edge of the upper grille panel. This is from an ancient US Camaro Club ad. The owner of the car was looking for others.

I'm sorry Charlie. It just occurred to me you won't be able to sleep until you find one!

Tenney
06-27-2019, 04:41 PM
https://i.postimg.cc/FHwFdLv4/ttt.jpg (https://postimages.cc/)

Is this what the hood stripe would have looked like?

Ultra-rare RHD COPO?!

the427king
06-27-2019, 05:43 PM
Rare reverse printed license plate too,along with a LH antenna,reverse stamped camaro header emblem, and opposite direction wiper arms . LOL

Lee Stewart
06-27-2019, 06:21 PM
Ultra-rare RHD COPO?!

https://i.postimg.cc/5tWcFSZJ/yy.png (https://postimages.cc/)

It was the only 1969 Camaro I could find that had a single hood stripe. LOL - didn't realize that the image in the photo was reversed.

Unreal
06-27-2019, 10:25 PM
https://i.postimg.cc/FHwFdLv4/ttt.jpg (https://postimages.cc/)

Is this what the hood stripe would have looked like?

That's what it would look like in your rear view mirror.

Charley Lillard
06-28-2019, 01:11 AM
William !!!!!!!!

Mr70
06-28-2019, 11:39 AM
...you have a Fish on the line William.

JoeC
06-29-2019, 11:08 AM
I have been posting about this for over 20 years that I think the Tailfins & Bowties data and the Fran Preve numbers are high estimates for the number of COPO 427 cars built.

I feel the “700” number is more accurate since that is the number that Chevy used in the COPO service letters.

The Tailfins & Bowties data are numbers for RPO L78 and Z27 SS and I don’t see anything that indicates Chevy included the COPOs and 427 engines or that they excluded them.

To use those numbers you have to assume the COPO 427 options are included in the L78 totals and were not included in the Z27 (Camaro SS) total.

This may or may not be correct but it seems inconsistent to say Chevy considered the COPO 427 as a L78 and not an SS.
If they began as an L78, I would think they would be SS L78 before the COPO 427 conversion but we don't know how they were used in the RPO totals.

I don’t understand why people don’t use the “700” number as more accurate since that is the number that Chevy used in the COPO service letters

The Tailfins & Bowties RPO data and the Fran Preve engine numbers are both great sources of information but the “700” number is the number that Chevy used in 1969 as the number of vehicles built.

The Chevy COPO letters, that were reprinted in the COPO Connection book , said about 700 high performance vehicles were “in process” as of 7-9-69.

The 4 COPO letters document the build of the 9560 (ZL1) , 9561 (L72 Camaro) , 9562 (L72 Chevelle) and 9737 (Yenko Sportscar Conversion ). The 4 letters are dated 7-9-69 to 7-24-69 and states the total of these high performance vehicle orders are about 700.

I know some COPO 427 cars were built after 7-9-69 but I don’t think many were ordered after 7-9-69 .

The “700” number includes the 9560 (ZL1) , 9561 (L72 Camaro) , 9562 (L72 Chevelle).

This is about half of what the total is using the Tailfins & Bowties data and the Fran Preve engine numbers.

Attached a pic of the *700” number in one of the 4 Chevy COPO Letters reprinted in the COPO Connection book

70 copo
06-29-2019, 12:39 PM
Norwood Plant engineering had a hand full of 427 cars to test most evenings out back by rail load out during production.

The estimate came from the engineer who was responsible for the actual physical testing.

He stated he tested in total "several hundred cars" as a required control group from 427 production. Testing was limited to two cars per shift during the build period or a 50% production control grouping.

William
06-29-2019, 01:09 PM
The "approximately 700 total vehicles" was an estimate made during July, 1969. There were plenty of COPO Camaros built August 1969 through the end of production. All Camaro orders in the system at that time were built in July. When Camaro production resumed August, 1969 the body/confirmation number sequence had been reset to N100001. I have 41 VINs for cars built 08C and later not on order in July.

"This may or may not be correct but it seems inconsistent to say Chevy considered the COPO 427 as a L78 and not an SS. If they began as an L78, I would think they would be SS L78 before the COPO 427 conversion but we don't know how they were used in the RPO totals."

At one time GM Canada would send a copy of the page of system-generated build records a certain VIN was listed on. There would be 15-20 other VINs/build records on the page. I have many of these pages. The build records for COPO Camaros shipped to Canada ONLY list L78 and do NOT list Z27-even the ZL1. Those cars also list the COPO number. [True L78 cars will also list Z27]. The letter CDN later supplied also listed the options that way for COPOs. That means that when Chevrolet tallied up the option build totals at the end of production, there were 1,066 L78 cars that were NOT also Camaro SS.

The only explanation for that: 69 COPO 9560 Camaros, 997 COPO 9561 Camaros. The Fran Preve and T & B numbers support it. There is plenty of evidence that there were many COPO Camaros ordered and built long after the July letter. Known late MN/MO engine dates: 822, 906, 911, 916, 923, 1002, 1013, 1016. Known late BE axle dates: 908, 919, 927, 1003.

The July letter might include all COPO Chevelles ordered/built; not all COPO Camaros.

JoeC
07-01-2019, 11:22 AM
Fran Preve wrote an article "The Numbers Game" published in the April 1987 MCR. Total Camaro L72 engine production is shown as 1,015. He states:

"Remember that these numbers indicate the number of complete engines built for production and after sale use, and do not reflect actual COPO cars produced."

He mentions an error rate of about 2% relative to actual car production. That's about 20 L72 engines. Do the math.
.


I did the math

the SHP 427 engine production to car production percentage is way over normal on 3 of the 4 special HI PO builds

The Fran Preve article "The Numbers Game" said that engine production was 2 to 5 percent over car production . He was talking about regular production engines and cars and he must not have known the COPO 427 car production numbers at the time of the article (1987)

Here are the numbers I have on the 427 COPO engine production to car production percentage and included the ZL1 Corvette since it was also a special HI PO build

ZL1 Camaro 88 engines to 69 cars = 22%
L72 Chevelle 358 engines to 323 cars (using RPOs) = 10%
L72 Camaro 1015 engines to 997 cars (using RPOs) = 2%
ZL1 Corvette 94 engines to about 3 cars = about 96%

JoeC
07-01-2019, 11:30 AM
There is plenty of evidence that there were many COPO Camaros ordered and built long after the July letter. Known late MN/MO engine dates: 822, 906, 911, 916, 923, 1002, 1013, 1016. Known late BE axle dates: 908, 919, 927, 1003.

The July letter might include all COPO Chevelles ordered/built; not all COPO Camaros.

20 years later and it is still an interesting discussion to me :)

How many L72 Camaros could have been made after the end of July? Maybe 100?

Using the RPO L78 and RPO Z27 SS totals it comes up with 997 L72 Camaros produced.

Chevy COPO letters state about 700 COPO 427s were “in process” as of 7-9-69. (includes ZL1, L72 Camaro, and L72 Chevelle)

That would mean less then 500 L72 Camaros produced by July 31 .

Chevy would have had to make another 500 L72 Camaros after July 31 to get up to the 997 total

William
07-01-2019, 04:18 PM
Tonawanda did not produce engines on spec. They were built based on demand from vehicle assembly plants. Tonawanda built 1,373 Camaro/Chevelle L72 engines. For '700 total vehicles' to be correct means about 700 L72 engines were produced for no reason. Really think they did that?

"That would mean less then 500 L72 Camaros produced by July 31."

By July 17th, Tonawanda had produced 920 Camaro L72 engines. The various data bases out there have over 400 COPO Camaro VINs built as of the July shutdown at Norwood. There are plenty of unknown COPO Camaros; the famous Mac's Chev photo dated June 1969 shows 8 COPO Camaros on their lot. Only one is known. Courtesy Chev in Sebring OH had some; none known to exist.

"The Fran Preve article "The Numbers Game" said that engine production was 2 to 5 percent over car production . He was talking about regular production engines and cars and he must not have known the COPO 427 car production numbers at the time of the article (1987)."

What difference would it would have made if he did know? Fran clearly states where he got the data:

“The numbers are taken directly from Chevrolet’s Summary of Engines Shipped.”

Why do you continually second-guess his data, obtained directly from Tonawanda production records by an employee, 18 years after production?

“…and the Fran Preve numbers come close but there are questions on the accuracy…”

Who knows better than an insider with complete access to production data?

Here is a COPO Camaro build record for a car shipped to Canada. Lists L78, 9561, no Z27. Why are there 1,066 more Camaro SS engines [L48, L34, L35, L78] listed in the T & B totals than total Z27 Camaro SS production?

bergy
07-01-2019, 10:23 PM
As supervisor on the charging floor of the Tonawanda Foundry, I also had supervisory responsibility over the briquetting operation. We would receive train car loads of iron borings from the Tonawanda Motor Plant and run them through briquetting dies to make them suitable for re-melting in the cupolas. One day, we received a complete ZL1 engine buried in the borings! It turned out that the 3rd shift clean up crew at the motor plant was dumping ZL1s on top of the borings in the rail car and covering them up. Then - over in the switch yard (off of Chevrolet property) - they would dig them out and take them. The whole operation was stopped and some employees got fired after we reported what we found in the rail car. No telling how many ZL1 engines they stole before the operation was stopped. Rumors in the plant indicated that it was going on for months, but certainly not every night.


Not sure if these engines were stolen before they were counted in production totals or after. I did reach out to Fran to discuss this issue before he died, but he didn't have much interest in the subject. I'm not sure when Fran was PM at Tonawanda. I was at a lot of meetings at the motor plant, but don't recall Fran.

Just offered this tid-bit to add confusion to the production totals!

Mr70
07-01-2019, 11:45 PM
Wow,how complete were the ZL-1's?...air cleaner to oil pan to water pump?
And didn't some of the borings get inside the engine?

bergy
07-02-2019, 12:04 AM
The one that we found was wrapped in plastic. Built intake to pan - can't recall WP. The ZL1 blocks were machined on their own CNC machining center up by the offices - very state of the art at the time. I'm not sure if they were even assembled on the regular production line. I didn't work in the motor plant - just passed by the ZL1 machining center on the way to QC meetings over there.

Kurt S
07-02-2019, 05:05 AM
I've stared at the production numbers for years. It took a long time, but I completely buy into the 997 COPO 9651 number.
More proof - there are more than 500 L72 cars in the database. That's 50%, which is very high. Nothing like $ to help drive the search!

markinnaples
07-02-2019, 01:30 PM
bergy, wow, that's a crazy story, thanks for sharing that. I can only imagine all the stuff that you guys have seen over the years. Thanks again for giving us a glimpse of what it was like back then, you guys are so valuable to all of us here.

Keith Seymore
07-02-2019, 03:53 PM
The one that we found was wrapped in plastic. Built intake to pan - can't recall WP. The ZL1 blocks were machined on their own CNC machining center up by the offices - very state of the art at the time. I'm not sure if they were even assembled on the regular production line. I didn't work in the motor plant - just passed by the ZL1 machining center on the way to QC meetings over there.

When I was on the traveling launch team one of the things we would do is get together and swap "misappropriation" stories from the various final assembly locations.

(ie - windshields layered between two pieces of cardboard and used as an umbrella; thermos filled with paint, etc)

K

markinnaples
07-02-2019, 06:36 PM
And you as well Keith, I've enjoyed hearing your tales from those days as well!

Sounds like an interesting place to work, thank you for sharing.

JoeC
07-06-2019, 11:52 AM
The "approximately 700 total vehicles" was an estimate made during July, 1969.



If you read the 1969 COPO letters from Chevy they do not say the 700 number as just an estimate. They are very detailed letters and looks like a lot of effort went into writing them.

The letter states the 700 number is from “ a complete review of the high performance vehicle area orders to date “.
They counted the actual orders for COPO 427s.

They had access to the Tonawanda L72 engine production numbers , why didn’t they use them?

We know more were ordered and built after 7-9-1969 but how many?

JoeC
07-06-2019, 12:04 PM
Tonawanda did not produce engines on spec. They were built based on demand from vehicle assembly plants. Tonawanda built 1,373 Camaro/Chevelle L72 engines. For '700 total vehicles' to be correct means about 700 L72 engines were produced for no reason. Really think they did that?



I don’t know how good the Chevy inventory control system was in 1969 but Yes I do think the engine production number can go much higher than the car production on SHP engines. They have a history of doing that.

The SHP 427 Corvette engine production went much higher than car production numbers (from Corvette web sites so not sure if they are 100% but was same on different sites )

1967: 277 L88 engines , 20 L88 Corvettes built
1968: 615 L88 engines , 80 L88 Corvettes built
1969: 213 L88 engines , 116 L88 Corvettes built
1969 94 ZL1 engines , about 3 ZL1 Corvettes built.

They even built SHP engines for cars that were never built
14 Engines built for the 1971 LS6 Chevelle , no production cars built

Some engines have been found with COPO suffix codes and no vin number stamped on the block.

Tonawanda built a lot of engines and stamped many different suffix codes

12 engine suffix codes just for 1969 396 Camaro/Chevelle
18 engine suffix codes just for 1969 427 Passenger

suffix codes just for a Heavy Duty Clutch or a Police package

JoeC
07-06-2019, 12:17 PM
Why do you continually second-guess his data, obtained directly from Tonawanda production records by an employee, 18 years after production?


Fran Preve did a great job getting the Tonawanda engine numbers and we are lucky to have them but some of his assumptions were not accurate.

In the 1987 article "The Numbers Game" He states the numbers do not reflect actual COPO cars produced but he said that the engines are 2 to 5 percent over cars.
They were not 2 to 5 percent over cars, they were 2 to 22 percent over cars

ZL1 Camaro 88 engines to 69 cars = 22%
L72 Chevelle 358 engines to 323 cars (using RPOs) = 10%
L72 Camaro 1015 engines to 997 cars (using RPOs) = 2%


In the 1990s he made the calculation subtracting the RPO L78 and Z27 Z25 numbers and assumed that all remaining cars are COPO 427.
This calculation result shows 997 COPO L72 Camaros and 323 COPO L72 Chevelles.

This assumption may not be accurate because it is not known how Police, Export, other COPO, F&SO , or foreign assembly plant units can affect the numbers.

There was some info found on non-SS 396 Chevelles.
This showed that the assumption all remaining cars are COPO 427 may not be accurate

Attatced a pic of a 1969 Police Chevelle brochure showing a 396 325 HP option.