Originally Posted by fyr
Excuse my ignorance as im a Norton newb but is the top an Atlas? or is SS a version of?
The Atlas was the 750cc version, but looks near identical to the 650SS and the last of the 650s, the Mercury, all of which were the linear descendants of the 500/600cc Dominator series.
1959 Dominator 88 500:
'63 Dominator 99/650SS:
'69 Mercury: (original factory colours, btw.)