Problem with pushrod shrouds is you cannot be sure that all faces align well enough for flat seals. That is dependend on compression plates and all, also the machining of shroud ends. So I decided on spherical washers on top of shrouds so misalignment is taken care of this and the shroud does not put sideloads on seals down low in the recesses of engine case. The o-ring on top of the nut is allright with misalignments, you just do the nut up with some respect to the rubber seal.
Vic
Vic