had been intended that the Sceptre be a sports saloon until shortly before its launch as a Humber, hence its sprightly performance compared with other Humber models. Nearly five years after its launch, a Singer Vogue Series IV saloon tested by the Britain's Autocar magazine in August 1966, now with an advertised power output of , had a top speed of and could accelerate from 0- in 25 seconds. An overall fuel consumption of was achieved. The test car was priced by Rootes in the UK at £911 including taxes, at a time when the Austin 1800 was retailing for £888 and the Ford Corsair GT was offered at £925. The performance was felt to be lively, and the gear change, supported on the test car with an optional overdrive, ‘crisp’ with well chosen ratios. Comfort and fittings were also commended, but the fuel consumption and the tendency of the heavy brakes to fade when used hard disappointed the testers: this would presumably not have been an issue had the road test been of a Humber Sceptre which had its stopping power from a servo-assisted front disc/rear drum arrangement. The Humber was also, at launch, fitted with a high tune version of the 1,592 cc and, from September 1965, 1,725 cc oversquare engine producing and respectively. Early models with the 1,592 cc engine had twin single Zenith downdraught carburettors - later 1,592/1,725 cc engines used a Solex twin choke downdraught carburettor for simplicity. The twin Zenith carburettors had been hard to keep balanced. Other modifications included a water-jacketed inlet manifold, timing adjustments and stronger valve springs to eliminate valve bounce at high engine speeds. The later H120's engine is a straight swap for both of these units and looks almost identical - it provides a useful boost in power to an already swift automobile. The unique Sceptre interior featured full instrumentation, including a tachometer marked up to 6,000 rpm, and a four-speed floor-mounted transmission with self-cancelling overdrive (with column-mounted control and indicator) on third and fourth gear for a total of six separate ratios in standard form. The lockout could be removed on first and second gears, and this was often done by Rootes in cars used for competitions such as rallying. In addition, the Sceptre was from the beginning provided with servo-assisted braking control and, unusually in 1963, 10-inch front disc-brakes. The Marks 1 and 1A were not available