1978 Mercury Grand Marquis vs. 1956 Rover P4
To start off, 1978 Mercury Grand Marquis is newer by 22 year(s). Which means there will be less support and parts availability for 1956 Rover P4. In addition, the cost of maintenance, including insurance, on 1956 Rover P4 would be higher. At 4,942 cc (8 cylinders), 1978 Mercury Grand Marquis is equipped with a bigger engine. In terms of performance, 1978 Mercury Grand Marquis (129 HP @ 3600 RPM) has 21 more horse power than 1956 Rover P4. (108 HP @ 4250 RPM). In normal driving conditions, 1978 Mercury Grand Marquis should accelerate faster than 1956 Rover P4. With that said, vehicle weight also plays an important factor in acceleration. 1978 Mercury Grand Marquis weights approximately 242 kg more than 1956 Rover P4. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Both vehicles are rear wheel drive (RWD) - it offers better handling in dry conditions; in addition, if you are looking to drift, both vehicles do the job better than front wheel drive vehicles. With that said, do keep in mind that many other factors such as speed and the wear on your tires can also have significant impact on traction and control. Let's talk about torque, 1978 Mercury Grand Marquis (303 Nm @ 2600 RPM) has 97 more torque (in Nm) than 1956 Rover P4. (206 Nm @ 2500 RPM). This means 1978 Mercury Grand Marquis will have an easier job in driving up hills or pulling heavy equipment than 1956 Rover P4.
Compare all specifications:
| 1978 Mercury Grand Marquis | 1956 Rover P4 | |
| Make | Mercury | Rover |
| Model | Grand Marquis | P4 |
| Year Released | 1978 | 1956 |
| Engine Position | Front | Front |
| Engine Size | 4942 cc | 2636 cc |
| Engine Cylinders | 8 cylinders | 6 cylinders |
| Engine Type | V | in-line |
| Horse Power | 129 HP | 108 HP |
| Engine RPM | 3600 RPM | 4250 RPM |
| Torque | 303 Nm | 206 Nm |
| Torque RPM | 2600 RPM | 2500 RPM |
| Engine Bore Size | 101.6 mm | 73 mm |
| Engine Stroke Size | 76.2 mm | 105 mm |
| Drive Type | Rear | Rear |
| Number of Seats | 5 seats | 5 seats |
| Number of Doors | 4 doors | 4 doors |
| Vehicle Weight | 1690 kg | 1448 kg |
| Vehicle Length | 5400 mm | 4530 mm |
| Vehicle Width | 1980 mm | 1670 mm |
| Vehicle Height | 1390 mm | 1320 mm |
| Wheelbase Size | 2910 mm | 2830 mm |
