Cork tappet chest cover gasket for 850-1098 engines and Cooper S up until 1966. Sold each, two (2) required. Ref: 12A1139, CKS809, 12A1139B.
Also check 12A1176 seal and 12A1177 cup washer for the tappet cover bolts when doing this job.
1966-on classic Mini tappet chest covers used the 12A1175 rubber gasket.
Important: If you are looking for a valve cover gasket, see GUG32VC. While these two gaskets are made of the same material (cork) and are similar in shape, they are not interchangable!