When did Chrysler begin pressure in cooling system?

I'm trying to use the stock radiator in my '36 Dodge. It is a non pressurized system. My 331 Chrysler New Yorker hemi, would that car have had a pressurised radiator or not? Thanks!

 

your 331 would have run with a pressurised sytem running around 7 to 9 lbs. The 36 would have a large top tank to allow for the water expansion as the engine heated up and there is a way to modify the radiator cap mounting neck to take a later pressurised ca. The earlier radiator will have enough capacity to cool the hemi in a stock or midly modified form and the conversion to a low pressurised system will help. I ran a small hemi in a 35 desoto (hence my nickname( and used the original radiator - all good

 

If you run Evans coolant you don't need to use a pressurized system.