Two Fleetwoods were available this year: The Fleetwood Brougham as a 2-door coupe and a 4-door sedan; and a Fleetwood Limousine as a 4-door sedan, 4-door formal limousine, and a commercial chassis.
While the innovative (but flawed) variable-displacement V8-6-4 engine no longer powered other Cadillacs, it remained active under limousine hoods for several more years. Fleetwood's standard limo seated eight. For an extra thousand dollars or so, the Formal limo held seven, with a sliding glass partition between compartments. A second control panel let passengers adjust temperature and power windows. Heather cloth interior came in black or dark gray-blue. Front compartment of the Formal limo was black, with black leather in seating areas.
| Feature | Limousine | Commercial |
| Type | V8-6-4 Variable Displacement | |
| Style | 90-degree, overhead valve. Cast iron block and head | |
| Displacement | 368 cu. in. (6.0 liters) | |
| Bore & stroke | 3.80 x 4.06 in. | |
| Compression ratio | 8.2:1 | |
| Brake horsepower | 140 at 3800 R.P.M. | 150 at 3800 R.P.M. |
| Torque | 200 lbs.-ft. at 1400 R.P.M. | 265 lbs.-ft. at 1600 R.P.M. |
| Five main bearings | ||
| Hydraulic valve lifters | ||
| Fuel supply | Digital fuel injection | 4-bbl. carburetor |
| VIN Code | 9 | |
| Model | Series Number | Body/Style Number | Body Type | Seating | Factory Price | Shipping Weight | Production Total |
| Fleetwood Limousine | 6D | F23 | 4-door Sedan | 8 | $27,961 | 4628 lb | 1,450 |
| Fleetwood Limousine (V8-6-4) | 6D | F33 | 4-door Formal Limousine | 7 | $28,941 | 4718 lb | |
| Fleetwood Limousine | 6D | Z90 | Commercial Chassis | N/A | N/A | N/A |
Figures before the slash are for V-6 engine, which was actually a $165 credit option; after slash for standard gasoline V-8. Diesel V-8 was also available.
| Feature | Limousine |
| Wheelbase | 144.5 in. |
| Overall length | 244.0 in. |
| Height | - |
| Width | 76.5 in. max. |
| Front Tread | 61.7 in. |
| Rear Tread | 60.7 in. |
| Standard Tires | HR78 x 15-D wide WSW |
| Feature | Limousine |
| Transmission | Turbo Hydra-matic (THM400) |
| Ratios | (1st) 2.48:1; (2nd) 1.48:1; (3rd) 1.00:1; (Rev) 2.07:1. |
| Standard final drive ratio | 3.08:1 |
| Steering | recirculating ball; power assist |
| Front suspension | coil springs and link stabilizer bar |
| Rear suspension | four-link, coil springs, elect. level control std. on limo |
| Brakes | front disc, rear drum |
| Fuel tank | 24.5 gal. |
1981