Norton Twin B/E Sizes + Bore and Stroke.

Dominator

88 Twin                        B/E Sizes............ 1".500 - 1".5005

99 Twin

1953 on 

500cc  Bore and Stroke........................ 66 x 72.6mm

600cc  Bore and Stroke........................ 68 x 82mm

SS 650 Manxman

Atlas 750

750 Commando               B/E Sizes............ 1".750 - 1".7505

    1968 on

850 Commando

647cc  Bore and Stroke.......................... 68 x 89mm

745cc  Bore and Stroke.......................... 73 x 89mm

830cc  Bore and Stroke.......................... 77 x 89mm