In reply to # 3888991 by riley1489 If one were to use both thermostat and this blanking sleeve, I would drill a larger hole in the sleeve and oriented correctly at assembly.
Unnecessary. The sleeve does not bottom out in the chamber in the head so with the thermostat closed you'll still have the same flow through the bypass that you would without it. Even when the thermostat is open some coolant will still go around it and through the bypass passages, but less than would without the sleeve.
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