Maserati's chief engineer Giulio Alfieri developed the two 2+2 prototype 3500GT, revealed at the Salon International de l'Auto in Geneva, March 1957. Both had a wheelbase and aluminum bodywork; one a superleggera body by Carrozzeria Touring of Milan, the other by Carrozzeria Allemano. The design incorporated
Minor design changes were done before production of the Touring-based body started late 1957. Front disc brakes and limited slip differential became optional in 1959, standardized in 1960; rear discs became standard in 1962. Borrani knock-out wire wheels complemented the standard steel wheels, as well as wider 185x16" radial tyres. All cars had leather interior and Jaeger-LeCoultre instruments. Power windows was added as standard.
In 1959 the Maserati 5000 GT was introduced, using the chassis of the 3500GT. Two steel-bodied convertible prototypes by Carrozzeria Vignale and Michelotti were developed in 1959 and shown at the Mondial de l'Automobile in Paris 1959.
The 3500 GTi and 3500 GTis was introduced in 1961 as the first fuel-injected Italian production car. It had a Lucas fuel injection (235 bhp). A 5-speed ZF S5-17 gearbox was now standard (3.02:1, 1.85:1, 1.29:1, 1:1, 0.85:1), as well as disc brakes all round. The body had a lowered roofline and become somewhat longer; minor outward changes appeared as well (new grille, rear lights, vent windows). The rather similar Maserati Sebring also a 2+2 coupe entered production in 1962.
The first year (1958) sold 119 cars, 1961 was the best-selling year totalling 500. All together, 242 Vignale convertibles and nearly 2000 coupes were manufactured, of these, 1973 being Touring coupe, the rest were bodied by other coachbuildes, Carrozzeria Allemano (four coupes, including the 1957 prototype), Zagato (one coupe, 1957), Carrozzeria Boneschi (two cars; 1962, 1963 Salone dell'automobile di Torino, 1962); Salon International de l'Auto in Geneva, 1963), Pietro Frua (two or three coupes, one spider) and Bertone (one coupe). The last was a coupe by Moretti (Salon International de l'Auto in Geneva, 1966).