auto tailsharfts have the same spline at the front as an L series car and they won't fit a manual A series box. I think all the tailsharfts were the same length from 1000 through to at least 180B. They changed the length of the yolk on the front of the diff. You may be able to make something work by swapping the yolk etc of the spare car, I'm not sure but I think most of the diffs had the same spline in the yolks.
Olboy