Well, different companies having different techniques I guess because my diesel shroud is enclosed all the way around (diesel mechanical fan though) and on a GM SUV, as well. Trust me, these are on-highway vehicles only. I was going on what I saw in my garage and what I read for OFF-ROADING:

Four Wheeler Magazine - "Keeping Your Cool: Cooling System Tech"
The fan shroud should cover as much of the radiator as possible. Don’t be afraid to trim the fan shroud slightly to clear the water inlet or outlet. Do make sure that the shroud seals against the radiator all the way around. It’s ideal to have the fan motor mounted 1 to 2 inches away from the radiator, although some tight situations call for a low profile fan setup like the one shown here.




Then Griffin radiators (King of the Hammers sponsor) has this from the Cooling Bible



As you can see, no gaps whatsoever, but these are off-roading designs. And really, when you look at my rig what is the first thing that pops to mind? How many highway miles does it drive or how much fun it is to off-road that thing? This is our third vehicle and only intended as "inclimate weather use" and off-road. I got a diesel and car hauler for extended trips. (Nothing made me sweat more than driving the Trooper 1200 miles to Moab, then off-roading it for several days while hoping I didn't break some unique expensive Isuzu part that would prevent me from driving the entire family back home and getting back to my job.)

Also, I've not got the steering monster figured out yet. Still have a constant drift the the right requiring constant turning to the left - even while driving a straight road. Adjusted the aluminum bumpstops to prevent the tires from rubbing the sway bar and track bars. Kept the axle on stands, kept tires off, ran the engine and it didn't move after 15 minutes of idling. Alignment is good on all three axis and squareness. I'll have to keep testing (same thing after driving several miles, maybe street tires, maybe new upgraded PS pump)...

Sam