If you're using a cross flow radiator (tanks on the sides) leave 2-3 inches of air space below the fill neck to let the coolant expand as it warms up. How far above the thermostat housing is the top hose connection in the radiator?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!