Jett, to explain the whys:
A lot of owners including myself have opted to "split" the radiator fan shroud in half to facilitate easy removal of only the top half of the shroud for any future work on the front of the engine. Some owners have advocated totally removing the bottom half of the shroud and discarding it saying it does not add much to the mechanical fan's efficiency. If you live and drive in cooler climate locations where ambient temperatures and relative humidity does not get to high, that certainly may be ok.

But in my case, living in the deep south where temperatures can routinely climb well above 100 degrees F and the relative humidity can be almost 100% in the hot summertime, so with the very high temperatures and humidity, I need ALL the cooling flow I can get so I opted to keep the bottom half of fan shroud just in case it helps to add any fan efficiency. Hang a 5-6k loaded trailer behind your Jeep in these conditions and you will find out real quick how well the performance of your cooling system is doing for both engine and transmission.
But to each his own, advice is free.



This was one of several good threads on LOST on how to split the shroud:> viewtopic.php?f=98&t=87178
Lots of good information on how some performed the split.

This was my design to allow the keeping of the bottom half of the shroud after cutting it in half:
Covered in detail at:> viewtopic.php?p=916154#p916154

This design allows the top half of the shroud to slide in-between (sandwich) two pieces of Lexan which hold everything securely in place and not allow it to move.