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Installing a Crossflow Radiator in a 1960 Corvette

Too Cool: A modern cooling system for a Vintage Corvette

Gerry Burger Nov 1, 2016
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Few things can take the fun out of driving a vintage Corvette faster than an overheating engine. Cooling the engine in all driving conditions requires a modern system with all components in perfect working order. Add air conditioning to the car and the cooling system becomes even more important.

Our 1960 Corvette is powered by a 348-cubic-inch “W-motor.” The concept is simple. If Chevrolet had built a big-block Corvette in 1960 this is the engine they would have used. As it turns out, the engine fit in the engine bay well, and coupled to a TCI Auto 700-R4 transmission we expect good performance from the engine. Starting with a base 250hp engine we added some headwork, a mild cam and dual-quad style FAST EFI throttle bodies. With these mods we feel comfortable designating the engine in the 325hp range. We mention this only because horsepower is heat and it is an important part of designing an effective cooling system.

Our car is also running Vintage Air A/C and that means a condenser mounted in front of the radiator. Our TCI Auto 700-R4 is externally cooled and that cooler is mounted in the grille opening as well, but we worked to keep it below the radiator so it would have its own stream of cooling air. Since the objective is to get as much cool air flowing through the fins of the radiator as possible, details such as transmission cooler location become important. By moving our TCI tranny cooler down low, just the very top of the cooler is in front of the radiator. Obviously, running a transmission cooler in the radiator is less than desirable as it adds heat to the cooling system and does a less than desirable job of cooling the transmission.

Armed with a horsepower rating and the model car the engine was in, it was a simple matter of calling U.S. Radiator to have a brand-new radiator built for the car. For the average Corvette owner the gut instinct is to go with an aluminum radiator since many of the factory cars came with an aluminum radiator. The factory aluminum radiator is nowhere near the modern aluminum radiators. The cooling tubes are much farther apart and the fin count is much lower. Since the hot water travels through the radiator tubes allowing the fins to absorb heat and then dissipate the heat into the air stream, the more tubes and the more fin area you have the more heat will be dissipated.

Like most Corvette owners, we asked about aluminum, and U.S. Radiator has aluminum radiators, but the tech on the other end of the line recommended brass/copper as their best cooling solution. Copper fins have superior heat transfer over aluminum and by using the U.S. Radiator Optima core we picked up 40 percent more heat transfer points than the original radiator. While they can build an exact replacement radiator in aluminum or brass, U.S. Radiator also has the capability to make custom units. Since this is not a restored car it made good sense to step up to modern cooling technology.

In the end we decided to go with a U.S. Radiator custom-built Optima core, triple-pass crossflow design radiator in copper and brass. This design gives us maximum cooling potential and the triple-pass design allows the coolant to remain in the radiator longer and contact more heat transfer points. This all adds up to a cool engine. However, all the coolant volume, radiator tubes and fins in the world cannot cool an engine without a good stream of air moving between the radiator fins.

We wanted to run an electric fan because they cool better in traffic than engine-driven fans. Electric fans also work well with our Billet Specialties Tru Trac system. The serpentine belt system drives our Edelbrock water pump along with the alternator and A/C compressor. There is a Tru Trac system designed for small-block, big-block and the W-motor families of engines, and the use of the Tru Trac serpentine system requires an electric fan.

As it turns out, selecting the correct electric fan was as simple as answering a few question from U.S. Radiator. They fabricated a very nice aluminum shroud that covers the entire core; ensuring cool air will be flowing through the core and not around the core. The fan is one of their thin-line fans leaving plenty of room between the Tru Trac and the fan. That completed our order.

A couple weeks later our custom-fabricated radiator and fan shroud assembly arrived. After removing the hood from our ’60 Corvette the radiator simply slid into place and four bolts later the radiator was installed. The unit fit perfectly with ample fan clearance. The installation couldn’t have been easier. Wiring proved to be very straightforward with a Ron Francis electric fan relay kit.

Since our 348 W-motor was not a factory option in a 1960 Corvette the hoses were a bit of a challenge. We bent a piece of welding rod to the approximate shape for both the upper and lower radiator hoses. A trip to our local auto parts store netted us several upper and several lower hoses, hoping we could find one that fit. As it turned out, after a little trimming a Gates 20345 solved our lower hose problem.

Our upper hose proved to be a bit more challenging. In the end we used two hoses spliced together with a hose splicer from Jegs and two shrink-style hose clamps from Gates. Since we want our engine bay to look like a factory installation we opted for conventional hose clamps at the radiator and water neck. This completed our radiator installation.

While we had the hood off and prior to installing the grille in our project car, it seemed like the perfect time to install the Vintage Air A/C condenser, dryer and associated plumbing. We mounted the condenser in front of our new radiator following the Vintage Air instruction sheet. This required cutting the “X-rod” crossbracing off the core support so the condenser would be close to the radiator. This close mounting ensures the electric fan is pulling cool air through both the condenser and the radiator. The Vintage Air supplied brackets locate the condenser perfectly (more on this in an upcoming A/C installation story).

Since we had to remove the crossbracing on the core support we thought it might be a good idea to add a horizontal brace to the top of the core support. Honestly, between the brackets for the condenser and the radiator our fabricated support was probably not needed, but our motto has long been, “When in doubt, make it stout.” A simple piece of 1/2-inch box tubing was used to make the brace and two holes were drilled in the front of the core support. A 1/4-20 bolt on each end holds the new brace in place.

The only thing left to do was fill the system with quality antifreeze and distilled water, check for leaks and fire up the engine. Let the engine run up to temperature and be sure the electric fan turns on at the desired temperature, we set our fan-on temp at 180 degrees and the entire system seems to function perfectly, cooling our big, bad 348. As we mentioned earlier, some simple planning, buying new, improved products along with a careful installation will net you a cooling system able to handle the summer heat.

Crossflow Radiator 2/20

01. When it comes to cooling a vintage Corvette engine, modern technology is the way to go. We ordered a copper/brass triple flow, crossflow radiator from U.S. Radiator to cool our 348 engine. U.S. Radiator also fabricated the aluminum shroud and attached the thin-line electric fan.

1961 C1 Corvette Crossflow Radiator Swap 3/20

02. We’ve all read this line before, “Installation is the reverse of removal.” Well, in this case it is true, the new radiator simply slides into our 1960 Corvette core support and we used four stainless steel bolts to hold it in place.

Billet Specialties Tru Trac Serpentine System 4/20

03. We are using a Billet Specialties Tru Trac serpentine system and Edelbrock water pump on the front of our engine. With the new radiator in place we still have 2 inches of clearance thanks to the very thin aluminum shroud fabricated by U.S. Radiator.

Gates 20345 Hose 5/20

04. Custom engine installations mean finding a hose that will work. We took several hoses home from our local auto parts store and finally settled on this Gates 20345 hose for the lower. We trimmed both ends to fit our application.

Gates 21852 Upper Hose Oreily Hose 6/20

05. The upper hose was a different story. Try though we might we could not find one hose with the perfect contours. In the end we used sections of two different hoses to fabricate our upper hose. A Gates 21852 and an O’Reilly Master Pro 20982 did the job.

1961 Corvette Crossflow Radiator Swap Hose Install 7/20

06. We installed the two hoses, one coming from the thermostat housing, the other slipped onto the radiator. We rotated the hoses until we had the best alignment, taking into consideration hood clearance and smooth radius bends.

Hoses Cut Points 8/20

07. We carefully marked the cut points on both hoses; we always mark an arrow on the cut side of the tape to minimize the chance for error. A sharp utility knife handled the cuts.

Radiator Hose Splicer 9/20

08. We ordered this radiator hose splicer from Jegs, along with two Gates Power Grip shrink hose clamps. These clamps are amazing, clean looking and they form a perfect seal.

Hose Clamps 10/20

09. We wanted a vintage, factory look under the hood so we opted for traditional hose clamps on the thermostat housing and the radiator. You can use a modern clamp or the factory original style. If you want a cleaner, more modern look, the Gates shrink clamps can be used throughout.

Gates Shrink Clamps 11/20

10. With the hose splice installed between our two cut hoses it was time to install the Gates shrink clamps. It is as simple as sliding them over the hose and heating them with a heat gun until they have a uniform shine.

Completed Fabricated Upper Hose 12/20

11. And here is a completed, fabricated upper hose. The Gates clamp give it the appearance of a single hose, a much cleaner look than two conventional hose clamps could provide.

Vintage Air Condenser 13/20

12. Since we had the hood off the car and we had not installed the grille we decided to go ahead and install our Vintage Air condenser. To that end the rod X-brace must be removed from the core support.

Cut Off Wheel 14/20

13. A cut-off wheel made short work of removing the X-brace from the core support. The Vintage Air condenser bracket will add much to the rigidity of the core support.

1961 Corvette Radiator Swap Top Brace 15/20

14. Even with the Vintage Air condenser installed, we thought it couldn’t hurt to add a top brace to the core support. The brace can be seen just above the condenser. The brace was fabricated from 1/2-inch box tubing.

Tapered End Crossflow Radiator 16/20

15. The ends of the box tubing were sliced, folded and welded to form a tapered end. Then a piece of flat stock was welded to the end of the box tubing. The tapered end allows the brace to slide into the core brackets.

Bracket 20 Nut 17/20

16. On the back side of the bracket we welded a 1/4-20 nut that will hold the brace in place.

1961 Corvette Steel Bolt 18/20

17. A single stainless steel 1/4-20 bolt on each end holds the brace in place. While a straight, horizontal brace like this is not as rigid as an X-brace, we felt that it added some strength to the core support with minimal effort.

1961 C1 Corvette Crossflow Radiator Swap 19/20

18. A quick coat of primer and semi-flat black and the brace was installed for the last time. Note the Vintage Air condenser is also installed at this time. The Vintage Air condenser brackets add a lot of rigidity to the core support, too.

1961 C1 Corvette Crossflow Radiator Insalled 20/20

19. And here’s the completed installation of our modern cooling system. The U.S. Radiator crossflow radiator looks perfectly at home in the Corvette and the electric fan is nearly invisible. We were pleased with our hose arrangement and are happy to say the 348 W-motor is one very cool engine.


Billet Specialties
La Grange, 60526
Vintage Air
San Antonio, TX 78266
Ron Francis Wiring
Chester, PA 19013
U.S. Radiator
Torrance, CA 90503



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