So far as I know this car's engine is a de Havilland Gipsy Major, adapted to run upright (rather than inverted) so nothing to do with the Great War (WW1 if that's how you think of it) or the USofA. The engine cannot be earlier than 1932.
There is nothing Brooklands about it either, as it was made by Frank Cuttel in New Zealand in modern times.
The person in the USofA who is offering it for sale says things that are plainly not true but are hoped to get him the $125k price. I understand he paid Frank about $AUS39k so he's got some work to do!