From the picture I note a couple things that need to be addressed. First of all, the pump is centered low on the radiator, the "short pump" pulley is not going to give you the proper pump rotation speed and the fan isn't helping your over-heating situation.
Having been faced with the same issues with my AD truck I used an adaptor plate and an "early" 216-235 waterpump to raise the fan up to draw air through the top of the radiator. I tried a pricy "short pump" and it gave me fan/radiator clearance but did nothing to improve cooling. The adaptor plate, which is available from one of the members of this forum as well as on Ebay, moves the pump up where it draws air through the top of the radiator which is where the hot water enters. The "early" pump has the correct pulley size (in both fan belt widths) and was available at a local NAPA. In addition, moving the pump up lets you run a 15" 6 blade fan (Summit FLX-1615P@$25.95)if you want. The center fan mounting hole has to be opened up to mount on the early pump snout. This is easily accomplished by scribing the correct hole diameter and working it with a rat-tail file. By moving the pump/fan up you also gain extra fan clearance from the generator/alternator/harmonic balancer pulleys.
Even if you did fabricate a shroud the low fan position and incorrect pulley size will not cure your overheating issues. Using the adaptor plate ($40.00) is the most common fix. I have a number of pictures in my Webshots albums that illustrate the installation process which is accomplished with hand tools with the engine in the truck with front sheet metal installed. My truck with A/C operates at thermostat temperature even with extended periods of idling, even with ambient air temps between 90-100 degrees F. In addition, if you use the 7 lb cap and fill the radiator only to the top of the core you will leave enough expansion space so you don't have to concern yourself with boiling over. I hope this helps you solve your cooling issues.
Dave
