Dion tube featuring inboard brakes on the first series, later changed to a more conventional Salisbury leaf sprung solid axle with a single trailing link on the second series. On both axles there were anti-roll bars. Brakes were solid Girling discs all around. A limited slip differential was optional. Engines The long lived quad cam, all-aluminium Maserati V8 engine made its début on the Quattroporte. It featured two chain-driven overhead camshafts per bank, 32 angled valves, hemispherical combustion chambers, inserted cast iron wet cylinder liners, and was fed through an aluminium, water-cooled inlet manifold by four downdraft twin-choke Weber carburetors—initially 38 DCNL 5 and 40 DCNL 5 on 4200 and 4700 cars respectively, later changed to 40 DCNF 5 and 42 DCNF 5 starting from December 1968. Special models (AM121, 1971 and 1974) In 1971, Karim Aga Khan ordered another special one-off based on the Maserati Indy platform. Rory Brown was commissioned as the chief engineer of the project. The car received the 4.9-litre V8 engine (Tipo AM 107/49), rated at . Carrozzeria Frua designed the car, the prototype of which was displayed in 1971 and 1972 in Paris and Geneva respectively. The car was production ready, even receiving its own chassis code (AM 121), but new owner Citroën used their influence to have Maserati develop the SM-based Quattroporte II instead. Only two vehicles were finished, chassis #004 was sold by Maserati to the Aga Khan in 1974, and the prototype #002 went to the King of Spain, who bought the car directly from Frua. Quattroporte II (AM123, 1974–1978) The second generation Quattroporte, named Maserati Quattroporte II (AM 123), was introduced at the Paris Motor Show and the Turin Motor Show in October 1974. As the result of Citroën’s joint-venture with Maserati in 1968, Quattroporte II was very different from its predecessor and the other Maserati cars in the past. Basing on a stretched Citroën SM chassis, Quattroporte II featured the mid-engine, front-wheel-drive layout, hydropneumatic suspension, four fixed headlamps with two swivelling directional headlights, and V6 engine. The bodywork was designed by Marcello Gandini at Bertone. Maserati had planned to equip Quattroporte II with V8 engine, but the Maserati’s Tipo 107 V8 engine was too large for Citroën SM chassis and too obsolete. A prototype 4.0-litre V8 engine was built from two compact Citroën-Maserati V6 engines. Maserati cut through the rear cylinders in half on one block (2.5 cylinders per