Think that larger crossmember in '54 might have just been
because the HM was now being offered as an option? Even though
the rear of the HM was supported there was still more weight on
the rear engine mounts with the HM than with the other options.
As far as I know there never was a problem previously,
cantilevering the 150lb SM420 from the bell housing. The whole
works, engine and trans being mainly supported by the rear
engine mounts, kind of like a teeter tauter favoring the front
or engine side.
DG
