From my Clausing / Colchester 8000 series manual
Headstock alignments . insert 2" diameter steel bar in chuck. Do not support.
2. Take roughing cut. take light finishing cut over the 6" length.
3. Micrometer readings taken both ends.
4. Lathe power off, idler gear, swing frame clamp nut off.
5.Slacken 4 headstock securing screws.
6. Adjust the set over pad to pivot headstock. Small adjustments only are necessary . On your test piece if point A is chuck side, and point B is tail stock side then. As a guide ,with a dial indicator set against point B of the test piece it will be necessary to swing the headstock approximately 2 1/2 times the difference in micrometer readings between point A and point B ( Take your readings at both ends of your test piece. Use point B for your adjustment gauge. )
7. Tighten the headstock securing screws swing frame, refit idler gear repeat and test cut . REPEAT AND REPEAT AND REPEAT.
Good Luck hope it helps
Frank