[Shotimes] T'stat o-ring p/n?

[Alan Fanning]

It's been a few years (but not very many miles) since I last replaced the
t'stat on my '91 SHO. It now appears to have given up the ghost based on the
fact that the temp gage indicates the car is running cold.  Why a $25 t'stat
can't last longer than a set of tires is beyond my comprehension.

Anyway, I've got a RobertShaw t'stat I think I'll try - but it needs an
o-ring gasket to seal it to the housing. Anybody know if this is available
aftermarket and by what mfg'r?

    Alan