Get an infared thermometer. You can buy them for not much at any auto parts store. You can just point and get the temp of anything with this tool. It is money well spent, as you will use it more then you will ever believe. Start the car up in your driveway, let it idle. Check the upper radiator hose temp and the lower radiator hose temp. Let it warm up and keep checking the temp. The upper radiator hose should be warmer then the lower radiator hose. When the gauge in the dash shows "H" find the upper radiator hose temp and then report back to us. Hot water goes in the top of the rad and cooler water comes out the bottom.
This needs to be the first step, before any more money is spent.
FWIW, I run a warmed over 440 in a 4X4 truck with junkyard electric fan. Idling around the timber in the hot, humid midwest, and it does not over heat(90-100* days with 90-100% humidity). Pound it through the mud, idle down the trail, bounce it off 6000 rpms pulling on stuck trucks, and the electric fan cool it fine. I don't have a rad as nice as yours or shrouded like your fan is. You should be in good shape radiator wise, unless the t-stat is sticking, or the gauge is off. I strongly persuade you to troubleshoot before dumping more money.
