I was looking up some parts and on the parts list there were two part numbers for the same part. One was for a VZN18# and the other was for a RZN18#. So, I did a Google search and happened across this old thread. Since the information I just found out was sort of related, I decided to make a post letting people know the difference.
So, if you're looking up parts for your 3rd Gen and you see two different part numbers for the same part, pick the part number for the ZVN18# if you have a 6 cylinder and pick the part for the RZN18# if you have a 4 cylinder.
Hope that clarifies what I was trying to impart to people.