There are few things that make a street rodder’s life more miserable than a car that runs hot. A cooling system that belches steam like a locomotive or pukes the proverbial green river of death is not only annoying but is sure to shorten engine life and pretty much put the kibosh on any long-range traveling plans you may have.

When it comes to our Road Tour cars we simply can’t afford downtime that results from overheating problems, so to eliminate any possibility of engine temperature issues we routinely turn to Don Armstrong of U.S. Radiator. The company has been in business for over 50 years, and Armstrong has been there for 40 of them. He began as a delivery driver, worked in every facet of the operation, and now owns the place. Today under his leadership the company produces over 400 different radiators.

While Armstrong has years of experience and does constant research to stay up with the latest cooling system technology, he has one other unique asset—he’s a hard-core hot rodder who understands the challenges of keeping them cool. As he explains it, the core design not the material had the greatest effect on temperature drop.

While all radiator cores might look the same they perform vastly different based on tube spacing and fins per inch. The heat transfer points of a radiator are where temperature is actually allowed to leave the radiator and that occurs where the fins are bonded to the tubes. The more transfer points a radiator has the greater the temperature drop will be between the inlet and outlet. For comparison a ’60s-style core typically had tubes spaced 1/2-inch apart, that is 1/2-inch of fin between the tubes. By going from a two-row radiator to a four-row core design we were able to double the heat transfer points, which resulted in a 15-20 percent increase in temperature drop without changing the other variables, such as air or coolant flow.

U.S. Radiator offers four distinct core designs, the Standard that is found in most OEM-style radiators, the High Efficiency aluminum with 20 percent more heat transfer points, the High Efficiency copper/brass with 20 percent more heat transfer points, and the Optima copper/brass that uses 1/4-inch tube spacing with 1/4-inch fins that provides 40 percent more heat transfer points

Radiator materials have created quite a bit of controversy. In the ’80s, the Japanese came out with a core design in response to the need to downsize radiators that have become the standard in the industry because it was efficient enough to allow the re-introduction of aluminum (a less-efficient heat transfer material) at the OE level. By changing the tube spacing to 3/8-inch, a core design referred to as High Efficiency in the industry, more tubes or water passages and fins were allowed across the face of a core with a specific width in inches. The design was simple enough but proved to be very efficient in that more heat transfer points created greater temperature drop inlet to outlet. It should be pointed out that the move to aluminum radiator construction was purely financial. The raw materials necessary to build a radiator are purchased by the pound and a finished aluminum radiator weighs about 25 percent of a copper/brass unit (dollars per pound being almost equal at that time). The result was a huge financial savings for the car companies.