There are really only 3 different type drums, they are all same dimensions inside though (7" bore) and take the same brake shoes, 1-1/4" wide on rear..
Flat drums- used on all Minis with 3-1/2" wide rims, including 997-998 Cooper and Clubby.
1" spacered drums- used on Cooper S, Clubman GT and Clubby S.
3/4" spacered drums- used on big wheel Mokes.
Note the Cooper S and Clubby S drums have all the same dimensions, but the Clubby S one has a plain bore in the hub where the Cooper S/GT is cast a fluted shape. Both these drums fit the same...
Note if using spacered drums you need the longer wheel studs...

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
