Take a look at the optional thermostat blanking sleeve pictured at the right. The small holes in the side are to allow air to escape during filling of the coolant. This part is intended to be used for racing applications, or whenever the engine may be run with the thermostat removed, such as may be done in very hot weather conditions. Note that the thermostat should never be removed during cold weather running conditions. It does completely remove any restriction to flow that a thermostat may create, and it does prevent any coolant from bypassing the radiator, so the warm weather racers love this little device.

The blanking sleeve replaces the thermostat and covers the bypass port in the cylinder head to direct all of the coolant flow through the radiator at all times. (Position small holes to either side of the bypass port). This makes for a much longer warm up period for the engine as it has to preheat all of the fluid in the entire cooling system before the engine will come up to normal operating temperature. It also means that the engine will never be able to achieve normal running temperature in cold weather, the carburetors may need to run on partial choke at all times, and the heater will not work well. As such it is not recommended to use the blanking sleeve alone, except for very hot weather conditions.