Built to contest top events like the Mille Miglia and Le Mans, the 3000 CM (Competizione Maggiorata) was the ultimate version of the 6C race cars. This design extends all the way back to the pre-war 6C 1750 and the later 6C 2500 SS race cars, but uses a 3.5-liter engine.
The 3000 CM immediately trailed the 6C 2500 Competizione, but produced nearly double the horsepower with its much larger engine. Both used the 6C’s independent suspension but in shorter wheelbase than the production cars.
Three or four coupes were made by Colli for the 1953 Mille Miglia. Despite competition from Lancia and Ferrari, one of these finished second overall. Later the cars were brought to Le Mans were they recorded the highest top speed of 154 mph down the Mulsanne. Unfortunately, all three cars retired.
After Le Mans almost all the Colli Coupes were rebodied. One was fitted with a Zagato Coupe for Joakim Bonnier. Another was send to Boano for a new body and gifted to Argentinian president Juan Peron. A third was bodied by Pininfarina into the Superflow concept car.
A few spiders were also built by Colli for Alfa Romeo and one of these won the 1953 Supercortemaggiore at the hands of Juan Manuel Fangio.
| type | Racing Car |
| built at | Italy |
| production | 5 |
| engine | Inline-6 |
| position | Front, Longitudinal |
| aspiration | Natural |
| block material | Cast Iron w/Aluminum Alloy Cylinder Head |
| valvetrain | DOHC, 2 Valves per Cyl |
| fuel feed | 6 Weber Carburetors |
| displacement | 3495 cc / 213.28 in³ |
| bore | 87 mm / 3.4 in |
| stroke | 98 mm / 3.9 in |
| compression | 8.2:1 |
| power | 205.1 kw / 275 bhp @ 6500 rpm |
| specific output | 78.68 bhp per litre |
| bhp/weight | 286.46 bhp per tonne |
| body / frame | Aluminum Body over Tubular Steel Frame |
| front brakes | Drums |
| rear brakes | Drums |
| steering | Worm & Wheel |
| f suspension | Arms w/Coil Springs, Hydraulic Shock Absorbers, Anti-Roll Bar |
| r suspension | de Dion Tube Axle w/Coil Springs, Hydraulic Shock Absorbers |
| curb weight | 960 kg / 2117 lbs |
| wheelbase | 2250 mm / 88.6 in |
| front track | 1310 mm / 51.6 in |
| rear track | 1310 mm / 51.6 in |
| top speed | ~246.18 kph / 153 mph |
| key drivers | Juan Manuel Fangio, Joakim Bonnier |
| race victories | 1953 Supercortemaggiore |
