Point of clarification: The early Cessna 120-140-170 series were "ragwing" (fabric covered) and so the wing itself had very little torsional stiffness. The lift strut was a "V" strut, and (in common with many other ragwing designs) the outer wing incidence was trimmed by an adjustable fitting on (usually) the aft member of the V strut. (It used to be fairly common to rig both wings with 1 or 2 degrees of washout, to force the wing root to stall first.)
But the 140A and 170A introduced the metal-skinned wing, with enough torsional stiffness that only a single lift strut was needed. Incidence angle was thus established at the wing root. (The C-120 was discontinued about this time)