In theory they shoud be changed in pairs, but my experience of MG leaf springs is that no two are exactly alike. On one occasion I ended up stripping four new spings to make a matched pair. Morgan springs are smaller than MGB springs, and V8 MGB's do suffer from sagging springs - drivers side is worse as we've discussed before due to the effect of torque. Not only do they sag, but they also develop an S profile from the side. Whatever you do, keep the old springs as a source of extra leaves - just in case.
