Jim Hendershot could try tuning his 150-year-old square grand
piano to A=415 Hz which is one semitone below modern concert pitch.
Harpsichords are tuned to this pitch, as it was common prior to the
nineteenth century, although in the early days there was no such thing
as a standardised pitch, each region, or even town, having its own
standard.

Pulling an instrument up to a pitch higher than originally designed
will affect the tone colour as well as possibly damaging the structure
or breaking the strings.  Some modern harpsichords are made with
transposing keyboards which can be moved sideways to play either at
modern pitch or the older lower pitch so they can be used in concert
with either modern or old instruments.

Kind regards to you all,
Nicholas Simons