GregAgrest Greg most radiators will do the job of cooling if,
1 have a good cooling fan to pull the air through the opening of the car. Have to remember that over 50 mph the fans are no help and the speed of the car takes over.
2 Getting the hot air out of from under the engine compartment. If your car has louvers in the fenders add a couple of 4" marine fans to help at idle. 2 fans, wiring , relay, and switch, about $100.00 dollars. 640 cfm of air flow.10-15 degree drop under hood. I run 2 for motor compartment and 1 for trans tunnel to cool trans
3 Raping headers with heat rap. This is not cheap but also helps. I have the same rap on my car for 15 years. It has not rotted out the header tubes. My tubes where hot coated from ERA and this helps also to keep heat where you want it.
4 Radiator angle, Best mounting is straight up and down for max flow over fins. Some companies have the reclined setup. The air doesn't like to bent going through the radiator. ERA has a wind splitter to help bent the air into the radiator for better cooling. Side note, I like the 2 small cooling fans in the front of the opening, bottom line they don't do poop. They take up room, Block air flow, and turn clean air into dirty air. Remove and retest car with and with out. They are cool to look at.
5 Crack the hood any time you stop somewhere to help remove the heat from the motor compartment.
6 You have info about radiators and coolant/water mix.
7 Last, waterpump. Is it a high flow unit. In the old days there was 2 styles, a car with AC and one without. If your water pump has a back cover on it, remove and check for a disc that is welded or rivited to the impellors. THis stops reverse flow and cavitation inside the pump. You can buy a kit for about $12.00 to improve the pump. Last thing PULLEYS. IF you are running march, replace the crankshaft pulley to match the size of the water pump pulley. You want a 1 to 1 ratio. The 30% underdrive is great for cruising and even racing but a idle over heats most motors. Been there done this.
8 Thermostat size. 95% of motors are happy with a 180F unit. The problem with some of these is flow openings. I have been around the block with this on an FE motor. I ended up running a 383-440 Dodge unit. The housing needed to be trimmed but the center opening is almost 1/2" larger than the stock FE one. Add and 1/8" air hole to help remove air in system. Make sure unit is mounted to have hole at top if vertical mounted.
This is all the info you should need to put that monster in the car. You can also add heat shielding but IMO I think it works both ways of helps and causing more of a heat sink than removal. This is an up in the air issue.
Good luck, if spelling is bad, just got glasses and can't see the keyboard
Rick L.