I believe you are referring to vertical rather than horizontal alignment
since you say you "shimmed it up". I do not know but I suspect the
tailstocks were matched to the headstock height since I have a 9" South Bend
which has a thicker shim than would seem reasonable for wear correction. I
have seen some instructions somewhere for building up the tailstock with
permanent shims and re-aligning it. A major job should also involve the fit
and alignment of the ram so that center-to-center alignment does not change
with ram extension.
Don Young

"David Rinker" wrote in message
news:gYgDf.1436$8U2.466@trndny06...
I have a 9" tail stock that out of horizontal alignment. I shimmed it up to
the level of the headstock to line it up. Can I replace this headstock with
another or are they machined to fit each indivdual machine.