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Found: 1955 Cadillac Eldorado 'Seville' prototype

A unique 1955 Eldorado built for the chief engineer of Cadillac

By Angelo Van Bogart/copyright Old Cars Weekly

Just when I thought all of the one-offs and prototypes were discovered, one popped up in the July 2015 The Self-Starter, publication of the Cadillac & LaSalle Club.

Tucked in the classified section at the back of The Self-Starter was a small photo and description of a very special 1955 Cadillac. Most people probably glanced over the ad, figuring it was a production 1956 Seville rather than the unique car it is. Had I not been so enthralled with 1955 Cadillacs in general and 1956 Eldorado Sevilles, I would have probably looked past the ad and then moved on myself.

What made the 1955 Cadillac in the ad so special is that it’s an Eldorado two-door hardtop, which was not offered by the factory until 1956. What I was looking at was the 1955 Cadillac-based Seville prototype that I had been searching for since 2002.

An ad for the 1955 Cadillac Eldorado two-door hardtop in the July 2015 Self-Starter.

An ad for the 1955 Cadillac Eldorado two-door hardtop in the July 2015 Self-Starter.

That year, I was at GM Media Archives sifting through General Motors’ files while researching Cadillac history for the book "Cadillac: 100 Years of Innovation." In digging through GM’s files, I stumbled upon a studio shot of a mid-1950s Cadillac Eldorado two-door hardtop and after closely examining the photo, I realized it had the 1955 Eldorado rear bumper and the six 1955-only hash marks between the bumper and bottom edge of the deck lid. This car was not a production 1956 Eldorado Seville two-door hardtop, but rather a 1955 Eldorado that was surely the prototype for the Seville that would debut during the 1956 model year.

Before discovering that image in 2002, I was disappointed Cadillac had not built the Seville one year earlier. While the Eldorado tailfins are identical from 1955 to 1956, the design of the 1955 Cadillac front end has always appealed to me more than the 1956 grille and bumper. Upon discovering that photo, I realized I wouldn’t have to someday build a 1955 Seville of my own by swapping a ’55 front clip onto a 1956 Seville — there was already one out there, at least in 1955. The question then became, Did it still exist?

With the question answered by the July 2015 classified ad, I contacted the seller. He explained that the current owner had bought the 1955 Seville in 1971 and stored it around 1980. The engine blew in the 1970s and upon disassembly, it was determined that the car's original, standard Eldorado dual-four-barrel 1955 engine had been built to the 1956 Cadillac displacement of 365 cubic inches. The car also had the revised 1956 Cadillac Hydra-Matic transmission, which required a unique shift indicator lens and decal since the 1955 transmission did not include park.

The seller also stated the original interior was upholstered in unique black-and-white material from neither 1955 nor 1956, but it was fashioned on the seats and panels to the design of 1956. The interior images he sent also showed the car had the chromed interior appointments one would also find on a production 1955 Eldorado convertible.

Unique cars such as this were given dated Shop Order numbers by General Motors design; these SO numbers were generally stamped on a tag that was installed on the cowl of each prototype or factory-modified car. The seller included pictures of this 1955 Cadillac’s tag which identified it as SO 2542 with a build date of June 6, 1955. This relatively late production date partially explained how it was possible for the car to have 1956 mechanical and interior features. The complete explanation was answered by the identity of the car’s original owner.

Factory photo of the 1955 Eldorado two-door hardtop. (GM Media Archives image)

Factory photo of the 1955 Eldorado two-door hardtop. Note the very metallic-looking paint job. This shimmering car would have stolen stares, even if people didn't realize it was a prototype for the forthcoming 1956 Seville. (GM Media Archives image)

In 1955, C.F. Arnold was the chief engineer of the Cadillac Motor Car Division of GM. He had joined the division in 1925 as an engineering department laboratory assistant and worked his way up to chief engineer by 1950. In cross-referencing a list of SO numbers supplied by fellow CLC member Jim Jordan, SO 2542 matched up to a 1955 Cadillac Eldorado and a “Mr. Arnold” — certainly the same Mr. Arnold who was chief engineer of Cadillac, and who would have been this car’s first owner as SO cars were built for show displays and/or high-ranking GM employees. (For example, Harley Earl's LeSabre, the 1955 Chevrolet Biscayne, each 1953 Buick Wildcat concept had unique SO numbers.)

Along with an image of the SO tag, the seller sent an image of the adjacent cowl tag, which answered how this unique 1955 Eldorado coupe’s body was built. Rather than fitting a fixed steel roof to a convertible 1955 Eldorado, GM pulled a Coupe deVille two-door hardtop from the line and then installed the Eldorado rear fenders and rear bumper. This is the manner in which Cadillac built production Eldorado convertibles from Series 62 convertibles, although the production Eldorado convertibles were differentiated from the Series 62 convertibles on the cowl tag.

In comparing the seller’s current images of his silver car to the light-metallic-colored car in the factory photos, almost everything seemed to match. The only difference was saddle trim on the belt line of the current car — the car in the factory photos lacked any beltline trim, even the standard 1955 Eldorado convertible beltline saddle trim, and recent photos of the car show a 1956 Cadillac Series 62-type beltline trim slightly different from the trim used in 1956 production.

Factory photo of the 1955 Eldorado two-door hardtop. Although it was clearly the prototype for the 1956 Eldorado Seville, no "Seville" scripts appear on this car. (GM Media Archives image)

Factory photo of the 1955 Eldorado two-door hardtop. Although it was clearly the prototype for the 1956 Eldorado Seville, no "Seville" scripts appear on this car. (GM Media Archives image)

Another minor inconsistency exists between the March 7, 1955, date on the factory photos and the June 6, 1955, date on the SO tag. Jordan’s list of SO numbers sometimes shows multiple entries for a single car, which can mean a car went back to GM design for some changes. Although only one entry on the SO list exists for this car, it’s possible the June date reflects a return of the car to GM styling for updates, during which time perhaps this trim was added.

When all the numbers and details are added up, it appears the Cadillac in the July 2015 TheSelf-Starter classified ads is the car I have searched for on the internet, in classified ads and in person and through other people, such as Jim Jordan, who searched for the car himself.

As much fun as the search and discovery of my dream car has been, and the fact that I take it as a sign that the car was photographed on my birthday, it’s not meant to be mine, at least not yet. I’m too sentimental toward my current fleet of ’55 Cadillacs to part with any of them to seal the deal.

The seller was listening to offers over the $25,000 mark, and it’s not a show-ready car. The original interior is not mint and some rust repair is necessary. It would be a shame to change the original interior since its upholstery is unique, and stitched special by General Motors for this car, but the rust would have to be addressed. Since the "mintest" 1956 Sevilles — if you can find them — are not worth much more than $50,000-$75,000 on their best day, this very-similarly styled 1955 Eldorado two-door hardtop probably wouldn’t be worth much more to anyone but the most die-hard 1955 Cadillac two-door hardtop fan who also happens to wish that Cadillac had produced an Eldorado Seville one year earlier. In other words, me. I hope that’s just the type of person who lands this very special car. For me, it will have to be another time.

-Angelo Van Bogart, editor, Old Cars Weekly

*Special thanks to David W. Temple for providing the GM biography of C.F. Arnold in conjunction with this car's discovery.

Read about more "barn finds" in "Lost and Found" Volume 2

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