i got hit from behind and pushed into car in front of me . clutch cable behaves as if it is too long . I have had to add bushings - washers to push it away from the firewall. i checked my wheelbase- 104 7/16" on passenger side, and, 105 7/16" on drivers side. Spec. says 105.1". would this significantly effect clutch cable?
No, since it is cable actuated the relative position of the pedal assembly and the clutch fork itself could change a lot and not affect the operation at all. That doesn’t change the fact that these truck’s been hit pretty hard and I’d guess the frame is racked. 1 inch difference in wheelbase side-to-side is quite a bit. Manufacturing tolerances may be as high as 1/2 inch so your truck probably dog-tracks down the road.
Your clutch cable has likely stretched, a lot.