Have a look on the RGM Norton web site. Under Technical Tips there is a useful page of Wheel Offsets for most Norton models.
If you have the correct (for 1955) 8" half width brake drum make sure you use the correct lacing pattern for the spokes, it is different from the 7" brake. The attached photo shows the spoke pattern.
Stephen,
Have a look on the RGM Norton web site. Under Technical Tips there is a useful page of Wheel Offsets for most Norton models.
If you have the correct (for 1955) 8" half width brake drum make sure you use the correct lacing pattern for the spokes, it is different from the 7" brake. The attached photo shows the spoke pattern.