The 3-litre was largely identical to the Pininfarina-designed Austin A99 Westminster and Wolseley 6/99 which used the same chassis and body. The Princess was given its own identity with a special Vanden Plas grille (fairly square, with a thick surround and vertical slats), round headlamps, and horn grilles on the front. The interior was lavish in typical Vanden Plas style, featuring burr walnut wood trim, leather seats and panels, and high-quality carpeting. A division between the driver and the rear compartment was an optional extra. Initially, it was powered by BMC's 3-litre C-Series engine, developing .