Have you considered the A arm bushing? Could point the right front wheel outwards if the front bushing pushes inward to the centerline of the truck or if the rear one pulls outwards from the centerline with the A arms now pulling in a forwards direction instead of tugged backwards from regular driving.

Its atleast worth checking for play in em with a prybar.

Are the c/v shafts the same length? My understanding of torque steer in fwd cars is from a longer shaft on one side.

89 v6 Raider 5spd
89 v6 Montero auto
86 TD Trooper