I work at a tire shop and have many Mopar clients.
Typical rule of thumb when is whatever the bias tire placard reads,add 6 psi for radials.
If the car calls for 26 psi,go to 32 with radials.
Most Mopars called for 24 psi up front,so go 30 .
Just a couple examples that work well with stock original or restored cars..
Cars that had any suspension or chassis mods or larger wheels & lo-pro tires will have to be set differently to work with said mods..
Hope this helps.
(BTW,yes my wagon is wearing the bias-ply in the first pic,LOL!! )