http://trove.nla.gov.au/newspaper/article/91620600
A report on the 1924 Motor Cycle Show in Motor Sport Magazine reads, in part:
NORTON. Stand 58.
Nortons are concentrating for the coming season on machines ... for solo and sidecar use. The big four has been slightly modified, and is now fitted with a larger diameter brake, of the internal expanding order. Its price is to be £670. The highest priced model is the overhead valve speed model, which is to cost £480.
Norton Motors Ltd., Bracebridge St., Birmingham.