Chrysler 300: Radiator Magnum compatibility
 

I'm somewhat baffled (and exhausted, but let's not get too humourous now..!)

In relation to coolant radiators on Rock Auto, I've seen:
'Mopar' with P/N 5137691AA reference a 'Standard Duty', P/N 5137692AA reference a 'Service Duty' (typo for 'Severe Duty'..?) and P/N 5170742AA 'Severe Duty II'.
Yet, other makes with P/N 5137691AA reference a 'Heavy Duty' (1.25" thick) whilst P/N 5137692AA is a 'Standard Duty' (1" thick).

How can these part numbers be reversed when made by non-Mopar manufacturers?

And will P/N 5170742AA 'Severe Duty II' for a 2005 Chrysler 300 fit a 2005 Magnum R/T without modification or additional parts?

I'm trying to get a bigger radiator for my R/T, but can't find out what my stock radiator is nor which P/N relates to a larger unit (for towing).

Can anyone shed any light on this please?

Thanks - D

Your questions should be answered from comparing parts catalogs from more than one source. Rockauto can be wrong as well as anyone else.