Six Cylinder Cam Followers/Tappets are available from:-
Arrow Precision Ltd
12 Barleyfield Services
Hinckley Fields Industrial Estate
Leicestershire LE10 1YE
Tel: 0044 1455 234200
Available on-line under Part No. CF124. However the prices have risen sharply but if sets [only availble in sets of 12] are ordered through Pegasus, we can supply at a better price.
Also available are racing cam followers which have a special diamond coating but see comment above.
By the way, the tappets for the 406 are a larger diameter. Bristol cars used to supply but it is not known if they still do. Arrow do not make them.