Swapping the 55-57 engine package for a late model power plant boosts performance and reliability in theses cherished classes cars. But whenever you mix old and new components, trouble is bound to follow especially engine cooling problems.
The original two-core radiator on the 55-57 wasn't designed to meet the cooling needs of a late model engine. In stock form, the two-core radiators on Tri-Fives had a core rating of seven psi or lower. That means the coolant/water mixture boiled at 233 degrees. That's find in a stock configuration, but whenever you upgrade to late-model engines, the cooling system must be upgraded as well to handle the excessive heat.
Late-model radiators offer a pressure rating of anywhere from 12 to 15 psi. The lower the pressure rating of a tank, the faster the liquid mixture inside boils. More psi allows the liquid to maintain a cooler temperature. Lower pressure cooling systems allow coolant to escape when the temperature rises, especially when the engine is turned off, and the coolant temperature rises to 225 degrees Fahrenheit or more! Suddenly, you are faced with a boil-over. Unfortunately, installing a higher pressure rated cap will do more harm than good, often leading to complete radiator failure. To find the psi for your radiator, check the cap or the owner's manual.
The Tri-Five classics come stock with a top flow, V-cell style of radiator, versus a cross flow, which is offered on late-model cars and trucks. The V-cell design greatly restricts the flow of coolant, which was fine for early V8 engines that operated at 160 or 180 degrees (this temperature being controlled by a thermostat). Later-model "smog" engines are designed to burn cleaner and leaner; however, the side effect is greater engine heat, with a normal engine operating temperature between 210 and 240 degrees! Your old-style, two-row, V-cell radiator will not, in most instances, be able to control the cooling of this type of engine, especially during summer or towing situations.
The answer is to update that old V-cell radiator, but without sacrificing the traditional good looks of the classic engine department. This is where Continental Radiator [* Now Mattson's Radiator] and Jack Mattson enter the picture.
Our predicament: we had a '55 Chevy two-door hardtop that was in need of a new power plant. We
wanted to upgrade the car with a 350 cubic inch, late-model engine, but the old radiator couldn't handle the heat produced by this motor. Jack of Continental suggested that custom top flow tanks with a "four-core" radiator would do the trick, and keep this baby cool. We nodded in agreement, and the actual building process was undertaken. By following the photos, you'll get an idea of what goes into custom designing a radiator of this caliber. Incidentally, Continental will custom design its radiators to your personal specs and ship them anywhere in the United States.
*All images are of Jack Mattson and his work and are copyright All Chevy magazine © 1990.