Bob, how are FE owners adapting the 5/8 UNF, 3/8 NPT, or 3/8 British pipe nut probe fittings from the Smith's Mechanical
Oil Temp guage to a 1/2" NPT internal threaded Aviad FE
oil pan welded fitting so the guage probe will contact the
oil, work and not leak.
The Smith guage with the ERA car had a pipe nut above the probe but the pan fitting is 1/2" NPT internally threaded (Aviad said so) and plugged with a cap.