Alright the heavy duty service groups contains:
136 amp alternator, 750 amp battery, heavy duty engine cooling, auxiliary oil tranny cooler, and transferase skid plate.

My radiator is going, and I want to keep the heavy duty cooling anyone know what radiator they used for these? or where I can find out?

 

Only one radiator for the v6 up to the 360 regardless of HD service . Single row 1.250". If you are planing on buying one i would suggest radiator.com they offer a lifetime warranty where the local stores only offer a year. I went threw two of them in two years so i learned my lesson. The one from radiator.com has been in for ten years.

 

If you plan to keep the truck for awhile, see if you can find an all-aluminum radiator, such as CSF 2969. This radiator will last a very long time, as there are no plastic tanks, which is a common failure point of the OEM radiator. CSF 2969 is also a perfect bolt-in swap. For more information, take a look at this thread:

https://dodgeforum.com/forum/2nd-gen...-radiator.html

At one time, this all-aluminum radiator was getting hard to find, however, it appears that CSF is continuing to make them again. Amazon and several other outlets appear to have them available.

 

Here is another one.

http://www.alumorad.com/dorampinewal.html

 

Be careful! I got one from eBay that said "all aluminum" but it had plastic side tanks. The guy said he meant "all aluminum CORE". It went back.

 

CSF 2969 is an all aluminum radiator. It is also the same radiator offered by AlumoRad. If you Google "CSF 2969 radiator", you will find it through several retailers.