A split case assembly for a gas turbine engine includes an outer diameter case defining a partial case structure for a gas turbine engine and multiple fixed-variable vanes attached to an inner diameter surface of the outer diameter case. Each of the fixed-variable vanes protrudes radially inward from the outer diameter case. Each of the fixed-variable vanes in the plurality of fixed-variable vanes is interfaced with one of a plurality of inner diameter boxes at a radially inward end of the fixed-variable vane, such that the inner diameter boxes define an inner diameter of a flow path and the outer diameter case defines an outer diameter flow path. Each of the fixed-variable vanes are interfaced with the one of the plurality of inner diameter boxes through at least one inner diameter shoe in a plurality of inner diameter shoes.