1984 Coupe deVille
New front-drive versions of DeVille and Fleetwood were anticipated, but delayed because of quality control questions; so for 1984 the rear-drive coupe and sedan carried on. Bodyside moldings were now color-keyed to the body finish. Taillamp lenses held goldtone Cadillac wing crests. All models now had electronic level control. The standard fuel-injected 249 cu. in. (4.1-liter) V-8 engine fed into a revised exhaust system with monolithic catalytic converter.
Electronic controls were modified to meet stricter emissions standards in high-altitude regions. The diesel V-8 remained on the option list, except in California because of its emissions Model regulations. Standard equipment included
The front-wheel drive editions appeared during the '84 model year as early 1985s.
| Model | Series Number | Body/Style Number | Body Type | Seating | Factory Price | Shipping Weight | Production Total |
| DeVille (V-8) | 6C | M47 | 2-dr Coupe | 6 | $17,140 | 3935 lb | 50,840 (total includes the 2-door Fleetwood Brougham) |
| DeVille (V-8) | 6C | M69 | 4-dr Sedan | 6 P | $17,625 | 3993 lb | 107,920 (total included the 4-door Fleetwood Brougham) |
| Feature | Standard Engine | Optional Engine |
| Fuel | Gasoline | Diesel |
| Type | 90-degree, overhead-valve V-8. Iron/aluminum alloy block; cast iron head. | 90-degree, overhead valve V-8. Cast iron block and head. |
| Displacement | 249 cu. in. (4.1 liters). | 350 cu. in. (5.7 liters) |
| Bore & stroke | 3.47 x 3.31 in. | 4.05 x 3.38 in. |
| Compression ratio | 8.5:1 | 22.7:1 |
| Brake horsepower | 135 at 4400 R.P.M. | 105 at 3200 R.P.M. |
| Torque | 200 lbs.-ft. at 2200 R.P.M. | 200 lbs.-ft. at 1600 R.P.M. |
| Main bearings | Five | Five |
| Valve lifters | Hydraulic | Hydraulic |
| Fuel supply | Digital fuel injection (single-point, dual injectors) | Fuel injection |
| Manufacturer | Cadillac | Oldsmobile |
| VIN Code | B | N |
| Wheelbase | 121.4 in. |
| Overall length | 221.0 in. |
| Height | (coupe) 54.6 in. |
| Height | (sedan) 55.5 in. |
| Width | 75.3-76.4 in. |
| Front Tread | 61.7 in. |
| Rear Tread | 60.7 in. |
| Standard Tires | P215/75R15 SBR WSW |
| Transmission | Four-speed overdrive automatic |
| Gear ratios | (1st) 2.74:1; (2nd) 1.57: 1; (3rd) 1.00:1; (4th) 0.67:1; (Rev) 2.07:1 |
| Standard final drive ratio | 3.42:1 except w/diesel, 2.93:1 |
| Steering | power recirculating ball |
| Front suspension | coil springs and link stabilizer bar |
| Rear suspension | four-link, coil springs, elect. level control available on DeVille |
| Brakes | front disc, rear drum |
| Fuel tank | 24.5 gal. except with diesel, 26.0 gal. |
1983