What were the most common racing cars of the 'golden era', 1920s-40s?

Question

I am referring to the grand-scale and romantic races of the 1920s through to the early forties across whole countries or lapping a track for hours at a time.

What cars were commonly seen? I can recall seeing a postcard once with an MG on it- the model began with 'M', I think...

Answer 1

the only M.G. open top touring car that was in production was the M. G. TC   but the better car of the day was of cause the old 140 Jaguar

Answer 2

In the United States, Offenhauser engines in an assortment of different chassis were competitive between 1933 and 1983. Ford's ubiquitous presence meant that many racerds would be based on Model T, Model A and Model V8 underpinnings.

In Europe, those witn a competitive streak woul have been running humble little Fiat Topolinos and  M Magnettes on the lowetr end. Higher-end machinery would have included 3-liter and 4.5 liter Bentleys, TType 35 Bugattis. bs would debut,and Mercedes-Benz and Auto Union.

Italy's races included Alfa omeo and Maserati