Most land speed cars, if they are allowed to by the rules, prefer not to run a radiator that exposed to the air because of the additional aero drag.
If you are loosing head gaskets and knocking out valve seats then you possibily need more water pump and you need to run the water system at high pressure, NASCAR runs at 75 psi and I have seen some over 150 psi. The radiator in a box allows you to basically run a standard radiator, which allows you to run high engine system pressure, in a container that carries water that cools the radiator. This allows you make a water container that is not pressurized and also because the radiator is in water the size of the radiator can be much smaller. A water to water heat exchanger is about 7 times more efficient that a water to air unit. The proper design of this type of system requires two water pumps, on to circulate the water through the engine and another to circulate the water with in the "box" through the radiator cooling matrix.
If you have a 1000 hp four banger you are obviously turbocharged and this means that you need a water pump that moves at least 100 gpm (10 gpm/100 horse power) at 40 to 50 psi. There is not an electric powered pump available today that will do that so you need to have an engine driven pump. You can use one of the electric pumps to circulate the water in the box but not the engine.
The other option is to use a water reservoir that can be pressurized to what ever you set your system pressure at and the volume has to be high enough that the amount of heat that the water adsorbs does not boil the water. The high pressure raises the boiling point of water and the high velocity of the water because you are using a big pump will substantially lower the possibilities of steam pockets around the exhaust valves that turbo motors like to make. The other advantage of the pressurized container is that you can fill it with water and ice which greatly increases its' capacity to adsorb heat because of the ability of ice to adsorb more heat when it transitions from a solid to a liquie. If you go with this route the only shape for the reservoir is cylindrical every other shape, square box, oval etc will deform and/or just blow up and if they are strong enough not to deform or blow up they will be very heavy.
The amount of heat that an engine dissipates through the cooling system is about 30 percent of the power that the engine produces. This does not mean that it is 30 percent of 1000 hp, in your case, it is 30 percent of the fuel energy that is used. So take your BSFC (Brake Specific Fuel Consumption, which is in lbs/horse power hour) times the hp times the btu energy per pound of fuel and it is approx 30 percent of that number. You can also take 30 percent of your shaft horse power divided by the estimated thermal efficiency of your engine (40 to 60 percent) and get the approx heat load.
A good cooling system can make an engine such as yours reliable or a poorly designed one can make it a grenade. Have fun and keep us up to date on the car as 1000 hp cars are usually very fast.
Rex