Great John
I'll make a start on them right away!
I found this line in the rules which seem to predict that something like this might crop up for this class,
"If, however, 1/24th scale racing proves popular then the standards can be expanded to cater for other periods"
I've checked out the cars and the geen #4 car is a Monroe, driven by Gaston Chevrolet to first place in 1920, I'll motorize this car but I think it will be too high and narrow to run at all well.
The #5 car is a Gilmore Speedway Special (Wetteroth chassis) driven to first place by Kelly Petillo in 1935 the first ever win for the four cyl. Offy engine.
This should convert quite well I think
BTW both these are Aurora kits.