The Montecarlo's origins trace to a Fiat project designated X1/8, commissioned from Pininfarina as a mid-engined companion to the smaller Bertone-designed X1/9. Initial design work was completed by 1969, with a final design by Paolo Martin finished in 1971. The first public offspring of the project was the Abarth SE 030 (also known as the Fiat Abarth 030), a racing prototype powered by a 280 hp 3.2-litre V6, which debuted in the 1974 Giro d'Italia automobilistico and finished second. However, the oil crisis of the early 1970s pushed the project toward a smaller engine, and Fiat transferred the X1/20 project to Lancia as a premium alternative to the X1/9.
Because the Montecarlo shared very few components with other Beta models despite carrying that family name, Pininfarina was commissioned to build the car in its entirety. The production car used a 1,995 cc twin-cam four-cylinder Lampredi engine from the Fiat 124 Sport Coupé, MacPherson suspension, five-speed gearbox, and disc brakes all round.
The Beta Montecarlo was unveiled at the 45th Geneva Salon in March 1975. The engine produced 120 PS (88 kW) at 6,000 rpm, with a claimed top speed above 190 km/h (118 mph) and a 0–100 km/h time of 9.3 seconds. The car was available as a fixed-head Coupé and as a Spider with a manually operated targa-style folding canvas roof.
Production ran from 1974 to 1982 with a 1979 hiatus, yielding 7,798 cars in total: 3,558 first-series and 817 second-series Spider models, plus 2,080 first-series and 1,123 second-series Coupés, alongside 220 competition units.
For the United States market, the Spider was federalised and sold as the Lancia Scorpion for model years 1976 and 1977, renamed to avoid conflict with the Chevrolet Monte Carlo. American emissions requirements necessitated a smaller 1,756 cc engine detuned to 81 hp (60 kW), along with larger bumpers and sealed-beam headlights. The Series One suffered from a brake balance problem — the power servo acted only on the front brakes, causing front wheel lock-up — which contributed to the production pause in 1978 while engineering changes were made.
The second series (1980–1981), marketed without the Beta prefix, incorporated updated styling including a new corporate split grille, glazed rear buttresses, larger 14-inch alloy wheels, and improved brakes with the servo removed to address the lock-up issue.
The competition version of the Montecarlo was the Group 5 Montecarlo Turbo, a silhouette racer that shared only the central body section with the production car. Front and rear tubular subframes carried the suspension and housed the mid-mounted engine, mated to a Colotti gearbox. Three engine variants were used: a 440 hp 1,425.9 cc unit, a 490 hp 1,429.4 cc version, and a 490 hp 1,773.0 cc engine.
Lancia entered the Montecarlo Turbo at the May 1979 Silverstone Six Hours — its first race in eight years — and won the 1979 World Championship for Makes (under-2-litre division). In 1980, the Montecarlo Turbo won the overall World Championship for Makes, and in 1981 it took the World Endurance Championship for Makes. Hans Heyer won the Deutsche Rennsport Meisterschaft in 1980 driving a Montecarlo Turbo, and the car placed first and second at the 1980 Giro d'Italia automobilistico.
The production Montecarlo also served as the structural basis for the Lancia 037, Lancia's Group B World Rally Championship contender. Developed for the 1982 season, the 037 retained the Montecarlo's centre section but was otherwise purpose-built, with a supercharged 2.0-litre engine mounted longitudinally rather than transversely. The 037 won the 1983 WRC Manufacturers' Championship, making it the last rear-wheel-drive car to win that title.
The Montecarlo's dual identity — a refined if imperfect road car and the springboard for two championship-winning competition programmes — gives it an outsized place in Lancia's history. The Montecarlo Turbo's consecutive World Championship wins in 1980 and 1981 were the peak of Lancia's sports car racing effort before the programme shifted entirely to rallying with the Delta.