The P4 90 was replaced in 1960 by the more-powerful P4 100. Its similar 2.6 litres (160 cu in) IOE straight-6 engine was in fact a short-stroke version of the P5 3-Litre unit. The car could now reach 100 mph (161 km/h). The interior was luxurious, with wood and leather accents on traditional English car elements like a curved "Shepherds Crook" handbrake lever. Either a bench or individual front seats could be ordered. A heater was a standard fitting. Like the smaller 80 version, the 100 was fitted with servo-assisted Girling disc brakes at the front, keeping drum brakes at the rear. Overdrive, on top gear only, was a standard fitting.
Production ended in 1962, by which time 16,521 had been produced.
Testing the 100 in 1960, The Motor magazine recorded a top speed of 92.1 miles per hour (148.2 km/h), acceleration from 0–60 miles per hour (97 km/h) of 17.6 seconds and a fuel consumption of 23.9 miles per imperial gallon (11.8 L/100 km; 19.9 mpg-US). The test car cost £1538 including taxes.
The final member of the P4 family was the P4 95 and P4 110 series. Introduced in 1962, the vehicles aptly represented the end of an era. Late in the run, the vehicles were fitted with steel door panels and electric windscreen washers. Although the Roverdrive automatic had been put to rest, overdrive was standard on the 110, whereas the 95 made do with a higher ratio differential (3.9:1).
Both models used the same 2.6 litres (160 cu in) version of the IOE engine. The wider availability of higher octane fuels permitted an increase in the compression ratio to 8.8:1, and the old unit now produced 123 hp (91 kW) in 110 guise, which used a Weslake cylinder head, and 102 hp (76 kW) in the 95.
After a successful run of some 15 years, the P4 series was replaced by the futuristic Rover P6 in 1964.
Rovers were owned by upper middle class big shots and aristocrats. This car represented Rolls Royce for them.Truly a car much before the time,it can even today,sucesfully be marketed. But perhaps Tata Group ,owners of Jaguar Land Rover may do so .