Ive seen many guys talking about how the upper manifold rots and will leak coolant. im looking for specific info about what this does where it happens how it happens anything to convince my dad that it would be a good idea to switch to a 180 degree t. stat anybody with anything would be great help thanks!

All over this forum and in Techinfo.

Where the EGR passes through the Upper mani, it erodes the wall clear through to a coolant passage. When that happens, coolant enters the intake then the cylinders. Depending on the size of the hole, it can use just small amonts of coolant, and make smoke, or large amounts of coolant and fill up a cylinder or 6 with coolant really fast and destroy piston rings or other important components of the engine.

A 180 will keep it cooler and proling life of the upper intake. There are redesigned manifolds and kits to fix the problem permanently.

A 180 degree thermostat will not prevent the problem. It'* the exhaust gasses from the EGR that run up through the EGR passage through the "stove pipe" that passes through the upper intake into the intake stream that burn the upper. A thermostat will not change the exhaust gas tempurature. Your only fooling yourself. The solution is to make or buy a new stove pipe that is about .100 smaller diameter OD than the OEM pipe. Then it will not contact the walls of the upper intake were it passes through. Look at the "Lower Intake Port Tube" in this link. http://ken-co.com/manifold/. I have not used this kit but I did make a new tube like the one shown when I replaced my upper.

There are several schools of thought on this one. One of those is that the cooler upper plenum resulting from the cooler thermostat will prolong the inevitable, by resisting the erosion through more efficient cooling.