Even though that is for a car it really isn't going to work that great especially when trying to cool 3 computers at once. An engine runs at 200F+ or 93C and the radiator is meant to handle those very high temps. So even though it is a heavy duty radiator it will not cool a computer any better than a normal pc radiator and it might actually perform worse. It's all about Surface area, Fins density, and Airflow. This radiator has a massive fan attached when not moving or highway wind speeds of 60+mph and has lower fin density due to the massive fan and forced airflow. I would estimate this radiator having the ability to act as a 3x140mm or maybe 4x120mm PC Rad.
What temperature a car runs at depends on the year, make, model, and design temperature. Two of the reasons engines run around 200F is for reliability, but mainly emissions. The reliability part is that the oil needs to be hot enough to evaporate the unburned fuel that gets into it
This is a problem or a potential problem with the small block chevy depending on how the coolant is routed. The thermostat on the SBC stops coolant flow when closed (unless modified) this has caused many radiators to crack (near the inlet), because of thermal shock. The thermostat does not open until it is over the temperature rating. The three common temperatures are 160F, 180F, and 195F.
The thermostat in a car engine is not there to keep it cool, but rather to keep the engine over that temperature. You can run an engine with the thermostat removed but they will run too cold. I ran an old l-head from a CJ with out one and it would never go over 150F, and was probably much colder when moving. Keep in mind that the CJ2A had a 4 cylinder, and a small radiator (single row around 19x13"). More recent radiators can have 1+ rows, and some of the heavy duty truck radiators are 4 row.
The radiator I have the core is around 17x25 inches, and with tanks is around 23x25". I know that these old trucks normally take around 4 gallons of coolant to fill from empty. I know this is not the best thing for an engine, but my old C10 had the heavy duty radiator, 454V8, and it would not overheat (even while towing) with the radiator at about half full. The inlet tank had cracked, and would leak coolant out above that level.
As for the car that is has a higher priority for now. If you can identify my profile picture accurately enough you can get a somewhat close guess as to what the car is.
PS
Also remember that a car engine runs on exploding fuel, and generate a lot more heat then a PC does.