I don't think this car is correct. Doesn't look right. Maybe caused by the restoration, but it could very well be a fantasy project looking a bit like the Alfa Romeo museum car that always attends the Mille Miglia.
It looks like it was an Alfa Romeo 1900 before it was wrecked and rebodied as a spider. Alfa Romeo did make some 4-cylinder racing cars in this general style during the period, such as the Disco Volante, but they looked different. https://en.wikipedia.org/wiki/Alfa_Romeo_Disco_Volante