Parts such as the Upper Casing: Ybs67-8 Washer, Spring, Gasket, Upper Casing (nas), Guide, Exhaust, Manifold, Exhaust are included in the 40j/ej/etj 1986 Upper Casing parts fiche.
The component with the lowest price in the UPPER CASING schematic is the Washer, Plain (663).
Of all the components used in this assembly the Casing, Upper is the most expensive.