1955 Ranch wagon with a 302 engine.

[poolplayer1]

I installed a radiator overflow tank/bottle on my 55 to capture any coolant that came off the radiator. My question is: Do I use the same radiator cap thats on there now? Its a 13psi cap without a pressure relief lever on it. A guy here in town told me that the cap had to be one that has a vacuum valve or something like that so that the coolant could be sucked back up to the radiator to refiil the radiator. What do you guys think about this? Thank you kindly for your help.