Looking for a Stant/MOPAR radiator cap for my 73 Dart

The only thing using a lower pressure cap might do is reduce the boiling point and possibly save marginal tubes from exploding. Seems to me a guy in the radiator repair business would WANT the radiator to explode so he could then repair it.

Here's the type of cap a '73 Dart or Duster came with. Nevermind the date code, the same part number is on my 49k Valiant.

http://www.ebay.com/itm/NOS-Mopar-3...cts-/371141382432?hash=item5669c01120&vxp=mtr