Re: Cooling system upgrade, 67, 350
Engine, make sure the timing curves and settings are done correctly. Ported vacuum advance and other bad considerations only help overheating and poor running.
Radiator: when done right, stock is just fine, multiple core, same.
Water pump: the impeller is the key here. Most late model pumps use an impeller that is stamped from a sheet of steel, and bent into fins, with NO backing to the fins, allowing coolant to bypass the fins, not push it through the system. The better pumps use either a cast, or special steel closed back impeller, so coolant cannot bypass the fins.
Drive pulleys: NO UNDER DRIVE PULLEYS, there is NO reason to turn a water pump slower than stock, ever.
Thermostat: Robertshaw, Mr. Gasket "Pressure Balanced" type, others do not have a barrel shaped valve in them as these do, they use a flat plate that can be forced closed at higher flow volumes. Temperatures for the thermostats, cast iron block and heads, 180 deg/F, cast iron block, aluminum heads, 192 to 195 deg/F., all aluminum block and heads, 200 deg/F.
Fan: full size ENGINE DRIVEN, not electric, with as many blades as will fit, no flex fans. The fan should sit 50/50 inside, and out of the opening in the shroud.
Fan drive: A/C fan clutch, they have a temperature adjuster on their front, to vary the fan drag to match engine temperatures. Non A/C clutches have a set drag ratio.
Radiator shroud: full size fan shroud that covers all the fin area on the radiator, even out to the end tanks, with NO fins exposed outside the shroud. Full air flow is needed for the entire fin and core row of the radiator.
Coolant: in areas with milder weather, 50/50 mix of anti-freeze and TAP WATER, hotter areas, can change the ratio to use more water, less coolant, down to 30/70 or so to match the need. Why tap water? Processed and treated waters are always mineral starved, so, they eat minerals all around them, like cast iron, aluminum, gasket materials, rubber water hoses. If you absolutely MUST use a treated water, add a sacrificial anode into the radiator and let the demineralized water eat the anode, not the rest of the system.
Of source, there will be people that will say all this is bunk, and that I don't know what I am doing, but, in the 50 years or so I have been running auto and motorcycle engines, not one of them has ever failed from doing what I just outlined above, and none of them ever overheated, even the ones I road raced. So, stupid me, this way WORKS.
You asked how to do it right, this is the way I learned to do it just that way, right.