A simple test to determine if a radiator is clogged up can be done with nothing more than the palm of your hand. After the engine has been run until your temps are up....SHUT IT DOWN and with the palm of your hand (or better yet an infrared thermometer) run it over the surface of the radiator core searching for spotty COOLER areas which will indicate areas that are clogged. Naturally, the top of the radiator should be evenly hot with even, cooler temps as you progress lower towards the return hose at the bottom. The clogged areas will be obvious. The core should be progressively cooler as you move down with no "cold" spots. Having a clean radiator is going to give you the proper potential for circulation. Once you get the radiator working efficiently, I'd make it a point to run a 12" heavy wire up inside the block at the block drain hole just in front of the oil pressure sender port. This passage, which opens up to the water jacket is often clogged solid with crud. You may even need to use an awl and hammer to break through the hardened crud. Running a hose into the open thermostat housing will commonly flush out a quantity of sludge that is restricting normal water circulation. On an engine that is torn down, even after being hot tanked, this passage can/will remain plugged. Removing the freeze-plug adjacent to this little port will also let you break up the hardened sludge that is causing hot spots in your block.
However, the only true way to correct your overheating woes is to use the adaptor plate and early pump to correct the misplacement of the fan and the incorrect fan rotation speed. Applying "band-aids" and "hoping" is just a waste of time and energy. The 216/235 does not need a shroud....if the fan is positioned to draw air across the top 1/3 of the radiator and the pump rotational speed is correct, as I mentioned in my earlier post. Taking the initiative to make the correct fix is going to solve the problem......the band-aids are just going to prolong the issue and detract from the fun you'll experience driving your truck without keeping an eagle-eye on the temp gauge.
Dave
However,
