Old racer car driver and mechanic trick. I a stat is not available, put an aluminum sheet or tin sheet in place of bonnet gasket. Put a 5/8" dia. hole in the sheet. This flows about the same amount of water as a stat and it does not fail during the race. To achieve lower temps than 180 degrees, you may have to play with the hole size.

Dale Duffield Tulalip, WA.
1927 Sports Cabriolet (since 1954)