Hot rodding has certainly changed over the years. Technology has enhanced virtually every part of the car, especially the internal combustion engine. Fuel injection, direct injection, plus supercharging and turbocharging, have given us engines that make 500, 600, and 700-plus horsepower, which not so long ago was unthinkable for a daily driver.
And while many electronic and mechanical components have gone high-tech, some components remain seemingly unchanged. The steering wheel is still round, we still use pedals for throttle and braking, and we still employ a radiator to maintain the proper operating temperature of the engine. Vehicles old and new utilize an open grille (save for the Corvette, Corvair and other bottom-breathing cars) to provide a fresh flow of air to the radiator.
The radiator is a necessary evil for liquid-cooled engines. The grille of any vehicle is part form and part function, and right behind it is the radiator. As a part of the design, the grille has got to be aesthetically pleasing—from an engineering standpoint it needs to have a large enough opening to let enough air reach the radiator, but not too big or additional drag will be encountered and fuel economy will suffer. The latter is far more important today than it was in year's past.
The next challenge is sizing a radiator for your engine, which is important when you have a modified combination. The type of driving you do and the horsepower (and engine type) will often dictate the size of the rad.
To handle the cooling needs for our Back To The Streets '71 Camaro, U.S. Radiator supplied us with the unit you see here. U.S. Radiator offers a wide variety of radiators for Chevrolets and other brands, and also different types of units, including original, aluminum, copper and its Optima series. Originally a lo-po small-block car, the Camaro's stock radiator was not going to cut it with our Chevrolet Performance ZZ454 crate big-block, especially considering the F-body now lives in South Florida and will have air conditioning.
The engine develops heat with every stroke and without a way to dissipate it, the engine would seize. The cooling system uses a water pump, fluid coolant, coolant passages in the block and heads, hoses, a radiator, shroud and cooling fan to rid the engine of heat so it can maintain a consistent operating temperature. In addition, the oiling system absorbs and dissipates some engine heat, but this alone would not be suitable.
Installing a new radiator is straight forward, as long as your new piece is of high quality and designed for the model and year car you are installing it in. In our case, we're going from a small-block to a big-block and from a track-only piece to a street machine, so we needed to increase the performance (capacity and efficiency) of the cooling system.
This also means selecting a cooling fan suitable for the job. Since we went with March's pulley system, we decided on an electric fan setup. Depending on clearance, you can go with a pusher or puller fan. A puller fan (one that mounts on the engine side of the radiator, is often better because it doesn't block the front of the radiator. It is equally important to have a proper fan shroud so the fan pulls air across the entire surface area of the radiator. All too often, people select a fan and shroud that is too small, which results in overheating.
Thankfully, the U.S. Radiator unit came equipped with twin-electric fans. Sized at 11 inches each, the system, with a really nice low-profile shroud setup, moves 1,600 cfm of air.
Of course you can use a stock-type mechanical fan, but they aren't as slick-looking, they rob power due to parasitic drag, and clearance can be in issue if you don't have a stock front engine accessory drive (FEAD). Electric fans can free up 10-20 rwhp, a nice bonus, and they provide a cleaner look. No matter what combo you have, we recommend installing new hoses (and clamps) when you replace your radiator. Chances are, if you are replacing an old rad, the hoses and clamps will be tired. This is a no-brainer.
Next on the list for our Camaro is the fuel system, so tune in as we install a new tank, lines and carb and regulator to feed the 454.