Merzario's first self-built Formula One effort, the A1, appeared in 1978 and was a basically conventional car based largely on his March 761B, with a red colour scheme and crude bodywork vaguely reminiscent of a Ferrari 312T2 in its use of cockpit-side ducting for an air intake.

For the Italian Grand Prix, both A1s were entered, with Alberto Colombo driving the original A1 and Merzario taking the newer second A1.

The car officially made its debut at the 1979 Spanish Grand Prix, where Merzario set the 26th time during qualifying and failed to make the race.

By this time, Merzario and Bellasi had purchased the assets of the Kauhsen team (and their driver Brancatelli), arguably taking on cars even worse than his old March-based vehicle.

[7] The A4 employed the same Cosworth / Hewland running gear and the suspension was similar to the A2, but the bodywork was less bulky, with better sidepods for improved airflow.

[8] However, Merzario did qualify and race the car in the non-championship Dino Ferrari Grand Prix at Imola, where he finished 11th and last, two laps down.

With March 812s, the team finally scored two podiums in F2, with Piero Necchi at the wheel, but after a lacklustre 1982 season, Merzario again built his own cars for 1983 with minimal success.