That's what I did on my Auburn. On the L-29 I used a rubber O ring but on disassembly I found the O ring out of position and resorted to gaskets for replacement.
CORDially Mike
This is a follow-up on Alsancle's subject on thermostats:
The NAPA Superstat #532060 is a perfect fit, but I found one small problem.
Because the new thermostat lies in a depression in the head, it will move up and down inside the housing as the coolant passes through. This allows a free flow of coolant, which causes it to remain in the 100 degree range.
An easy fix is to install a round cork gasket on top of the thermostat, same diameter of the thermostat. This acts as a shim to keep it from flopping around. Then you can assemble the outlet tube with it's gasket as normal.
