Automotive Mileposts  

1978 Cadillac Seville
Production Numbers/Specifications

September 29, 1977
56,985 (Seville only)
Series 6K/Style S69 4-Door Sedan $14,267
Weight: 4179* Built: 56,985
*Weight, as delivered with options: 4280

350 CID V-8 (5.7 Litres)
Bore and Stroke: 4.057 x 3.385
Compression Ratio: 8.0 to 1
Brake Horsepower: 170 @ 4200 rpm
Torque: 270 lb-ft @ 2000 rpm
Carburetor: N/A (Bendix electronic fuel injection)
350 CID Diesel V-8 (5.7 Litres)
Bore and Stroke: 4.057 x 3.385
Compression Ratio: 22.5 to 1
Brake Horsepower: 120 @ 3600 rpm
Torque: 220 lb-ft @ 1600 rpm
Carburetor: N/A (Bendix electronic fuel injection)
-- "400 Series" Turbo Hydra-Matic 3-Speed Automatic
-- 2.56 to 1
3.08 to 1 (standard with High Altitude Package; available option in California only)
GR 78-15B Uniroyal whitewall
Spare: G78-15B Stowaway
Wheels: 15 x 6 JJ
Power Front Vented Disc/Rear Disc, dual hydraulic system, vacuum assisted, self-adjusting
Total Swept Area: 474.0 sq. in.
114.3 inches
Front Tread: 61.3"
Rear Tread: 59.0"
Length: 204.0 inches
Width: 71.8 inches
Height: 54.6 inches
Ground Clearance: 5.4 inches
Weight Distribution (F/R, %): 57/43
Head Room: 38.5 front, 36.0 rear
Trunk: 14.9 cubic feet
Type: Power assisted recirculating ball
Ratio: Variable, 16.4-13.6:1
Turns: 3.0, lock-to-lock
Turning Circle: 42.34 feet
Seating Capacity: 5
Fuel Tank: 21.0 gallons
Cooling System:
1978 would be the best sales year for the first generation Cadillac Seville, and that would hold through the second generation Sevilles (1980-1985) as well.

First year for:

- Elegante trim option
- Trip Computer
- Diesel engine
- Electronic Level Control
- Opera Lamps
- Authentic Locking Wire Wheels

1978 Seville VIN Identification

Typical 13-digit 1978 Seville VIN: 6S69B8Q######

Decodes as:

Digit #1: 6 - GM Cadillac Division
Digit #2: S - Seville ('K' Body)
Digits #3 and #4: 69 - 4 Door Sedan
Digit #5: B - 350 CID V-8 EFI or N - 350 CID V-8 Diesel
Digit #6: 8 - 1978
Digit #7: Q - Detroit, Michigan Assembly Plant
Digits #8-13: Serial numbers begin at 450001

1978 Seville: At the Peak of Its Popularity

Image: 1978 Cadillac Seville

1978 would represent the high point for sales and production of the "first generation" 1977-1979 Cadillac Seville. The new Elegante trim package and the mid-year introduction of the Diesel Engine option likely helped contribute to the Seville's strong sales for the year.

The Seville had a reputation for being a very high quality motorcar, even by Cadillac standards, and former import owners were delighted to trade in their cars on an American model with softer seats, more amenities, and styling that was a bit flashier than what they'd had.

1978 was the second model year of the downsized Cadillacs, and they were being received very well. In fact, Cadillac set a new sales record for the third year in a row. Cadillac Division beat its 1977 sales by six percent, which was somewhat surprising given the rather hefty price increases for the year. Seville's base price increased by over $800, and the cost of most optional equipment went up as well.

And Cadillac's customers were ordering options at a record pace. Even with a long list of standard features, the list of accessories continued to grow as new things were added to the list. For 1978, three new radios were introduced, and Seville customers frequently upgraded from the standard radio. Two of the choices offered integral Citizens Band capabilities, which was popular at the time, before mobile phones were in wide use, and before cell phones became commonplace. One new radio for 1978 included AM/FM Stereo Radio with 8-Track Tape Player and a CB with a hand-held microphone unit with built-in controls for CB channel selection, Squelch, etc. A digital read-out on the hand-held unit identified the channel you were on. Pretty sophisticated for its time.

Seville's main competitors were luxury imports such as Mercedes-Benz and the Lincoln Versailles. Mercedes' total production for 1978 across all models was down from the year before, and overall less than Seville's for the year. Lincoln's Versailles got off to a good start when it was introduced mid-year in 1977, but sales declined sharply for 1978, with just 8,931 sold for the year. The Versailles received critical remarks about its styling. Not that it was bad, but that it was too much like the Ford Granada and Mercury Monarch, which were priced thousands less. While the Seville had rather mundane origins as well, Cadillac provided all-new sheet metal for the Seville, which hid the fact that underneath it was really just a Chevy Nova. Cadillac took huge steps to revise the ride and handling characteristics, as well as isolation from noise, harshness, and vibration.

The Seville would not enjoy sales figures like those of 1978 again. The 1979 model was almost identical to the '78, although changes were made to the body mounts and the suspension was retuned for a better ride, but externally you couldn't tell the difference. The second generation Seville that debuted in 1980 would have somewhat controversial styling, and would never reach the popularity of the 1978 body style.

Cadillac stated that the division "consistently leads all U.S. luxury car makes in repeat ownership." A fact, for certain, but Lincoln was gaining on Cadillac at the time, and the Continental Mark V was outselling the Fleetwood Eldorado by a huge margin. The Seville was without question the shining star of the smaller luxury segment.

The invasion of the expensive imports was a concern to Cadillac, but not necessarily an immediate threat at this time. What would become a threat was the continuing escalation of the cost of gasoline, as well as concerns over shortages. Wealthy Cadillac customers may not have been as concerned about the cost as they were the availability of fuel. They wanted to be certain they could buy it, regardless of price, when they needed it. And that was the predominant motivation for the move to smaller, more efficient cars that could go further between fill-ups.

The 1978 Seville is an excellent collectible, due to their high quality when new, complete list of standard features that make them comparable to even today's luxury cars, improved operating efficiency for the time, and availability of parts. These cars are great cars to drive, with adequate performance, interior luxury that can compete with new cars, and a solid, quiet, body that has held up very well over time. The electronics were sophisticated for their time, but can be troublesome today if they malfunction. We imagine it won't be long before improved replacement components are available, and our warning regarding leaking fuel injector seals applies to this year as well. Replace them if you aren't certain they've been done recently.