Depending on the cap type you want check for the valve hanging down. The numbers below were just the caps I had from my adventure in radiator caps and both were manufactured by MOTORAD, look identical and have no numbers stamped on them except the 16 lbs
This one will build pressure from the beginning of the heating of the cooling system (note the valve is closed)
(Carquest Premium Radiator Cap: 16 PSI 10231)
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This one will only pressurize after some spot boiling occurs (Note the valve is open, factory style)
Murray 16 psi Radiator Cap - 7616
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