the GSC brand takes its name from the initials of its founder, George Cyrill Stilwell.
To illustrate: a GSC 750cc Twin motorcycle, restored by Heroes Motors
Photo credits: courtesy of Serge Bueno
@sergebueno @heroesmotors
The GCS brand

In short
Years of production
We do not yet have a motorcycle specifications for this brand. But the site
moto -collection
will probably have information that fits your needs.