There is a gasket where the headpipe mates to the cylinder head which should be renewed each time the pipes are off. Its not readily apparent on a motor that has been run awhile as the used gasket looks like part of the head. Morgan uses the stainless mesh/graphite style as was used on Harley EVO motors from 1984. Many videos on youtube covering the replacement of these.
A tip from the local Harley dealer is to use the James brand copper wrapped stainless mesh gasket which is much easier to fit and seals without fail.
As for the exhaust stud nuts you can replaced them with a better design metal self locking 'jet nut' as used on aircraft. No need for the locking tab. They have the added benefit of only having a 3/8" hex (available in 6 or 12 point) which then allows use of a 3/8" socket with long extension.
Jet nuts installed. This was before I changed the pipe ends to a removable flange type as used on Harleys.
modified pipe end.
