The C/AIR roadster class was invented to fill a need that was not needed. They cried about how the Olds, Cad and early Hemis didn't have a class to run in. Bullshitt. They could run as a Gas Roadster in any displacement they fit in. Maybe not get a record, but they could run. But did that happen? -- No. Believe it or not, not everyone who runs think they can get a record in their class. D/AIR class for D-engined roadsters? What about AA, B, E, F, G, H, I, J, K classes for guys with Bantams, Pierce-Arrows, Lincolns, etc. Where does it end?
Want a record? Get a motorcycle. Read the Rule Book. There are hundreds of Open Records available.