The mode was done by Meto-Co-Aire in 1955 STC STCSA4-28.

The aircraft was put back on its tail 35 years ago. (Where it belongs!)
The inspecting A&P sent us this note.
I found where
Meto-Co-Aire installed a tri-cycle landing gear per
STCSA4-28 on3/7/1955. However, I need to find out
when it was
removed. I will let you know when I complete analysis
of the 73 pages of data.
once
an STC is applied to an Aircraft (major repair) adding
the tri-cycle gear there must be a Form 337 showing
removal. The records I received from AOPA shows the
installation but no removal. Therefore according to
GOD FAA the plane is not legal to fly until the Form
337 is processed and approved. You may want to advise
the owner of such.
What do we need to look for in the Logs?
Any input would be helpful.