Seventeen examples of the Type 61 "birdcage" Maserati were produced from 1959-61, had 250 hp from 2,890 cc in-line 4, and weighed 600 kg. Many were raced by privateers in the US, including Jim Hall and Roger Penske. They were a noisy presence at my local west coast track back in the day, although eclipsed by V-8 engine specials and rear engine Lotus and Cooper cars. At least one was licensed and operated on public roads.
They excelled at the Nurburgring 1000 km, with Stirling Moss and Dan Gurney winning in 1960, Lucky Casner and Masten Gregory in 1961.
A 2.0 liter version, the nearly identical Tipo 60, was also produced in fewer numbers.