Right radiator cap?

[az1966]

I've got a 13 lb rated radiator cap right now,,does anyone know if this is the right rating for my car?

thanks for help/info

200 ci,, 3 row copper radiator

 

[MPGmustang]

my 65 has a alum rad and a 16lbs cap. it gets hot in here in az so i like to keep the water in the system as long as possible.

 

[FalconSedanDelivery]

13-16 is fine