Correct PSI Radiator Cap for '70 340?

Food for thought............More pressure is harder on cooling system components, hoses, rad and heater cores

Depending on where you live, your altitude, you may not need such high pressure

I have a junk Dakota, and not long after resurrecting it, the heater core started to 'steam' Before that I had a 1/2T 5.2 Dodge, and later a 3/4T gas powered Dodge. All three have bad heater cores. To change the core you must REMOVE THE ENTIRE DASH. That is correct, remove the entire dash.

So I ripped out the pressure gasket and just run the caps with the upper gasket in place, which allows them to "slop back and forth" between the rad and the overflow tank. Yup. Sometimes I need to add some.