Musclecar Radiator Upgrade Options With Champion Cooling

championcoolingleadartGearheads typically develop a keen sense of smell over time. If someone’s burning oil, they can smell it. Race gas? Yeah, they know that smell any day of the week. And coolant leaks on a hot engine? That’s the burnt popcorn of the automotive world; the smell just lingers on in your vents and it becomes your primary focus until you find the source. Immediately, you look down at the temperature gauge, and once you’re in the clear you scan the area around you to find out who has the coolant leak – just to make sure it’s not your leak.

If you are noticing that smell around your own car and the temperature is actually creeping up past the 200 mark, then it’s a good sign that your cooling system isn’t performing as efficiently as it should.

This could be caused by a number of things, and Champion Cooling Systems has a series of videos to help you determine where your problems may stem from, and how to correct them.

With the subject of this installation, a ’67 Firebird, the hot Summer months were starting to cause the needle to creep up, and it was time to do something about it.


Often times during a build, the radiator is the last upgrade considered. Whether you’ve swapped a big-block for a small-block, or you’ve just decided on more power, like Ed Stutler did with his gorgeous 1967 Pontiac Firebird, Champion has hundreds of applications to help tame those cooling issues, and they can get you into the right radiator for the right price.

One of the more popular swaps these days is the LS swap, and the LS engine is being swapped into everything from imports to Fords, and much of the GM vehicle lineup. Champion is always busy finding new applications and expanding its line to include engine swaps in various vehicles.


We put an LS-style radiator (right) next to the direct replacement (left) and you can see that other than the two radiator hose fittings, the radiators utilize the same factory mounting location, so there’s no need to modify the core support for either radiator.

The LS-style radiator is a double pass design, which means the coolant passes through the radiator twice, which does help to keep the engine cooler. It’s not necessarily only for LS swaps; and with the early F-body radiators that we brought with us for test fitting, the Double Pass was pretty close to working on the BBC in this ’67 Firebird. The large, OE alternator was just a little too close for comfort, so Ed decided to go with the conventional style radiator.

Champion Cooling has hundreds of applications for classic cars and trucks, and in the case of engine swaps, they are working to provide solutions such as this double-pass radiator for LS swaps in the first gen F body.


Running Hot

Ed wanted to replace his radiator because after swapping in a warmed-over 454 into his Pontiac, he noticed that the needle began to climb at every stop light and sit dangerously close to the point of no return. Having been at many classic car and hot rod shows, he was familiar with Champion and knew that he better upgrade soon.

So why is it that classic cars today need bigger radiators, when the factory unit was just fine back in the 1960s? It all has to do with horsepower; and as you know more power means more heat. Factory radiators back in the musclecar era didn’t necessarily have to cool off high horsepower engines. Many of the cars back then were only capable of 150-250 horsepower. Big V8s were treated to three- and four-row radiators, but even then those engines didn’t produce the kind of horsepower that today’s musclecars are capable of.

The difference between Champion Cooling and many eBay radiators is that this is an application specific replacement. It won't require any fabrication or modifications to the core support, or any existing transmission cooler lines.

The LS swap we mentioned earlier is a popular swap because it’s an easy way to make over 400 horsepower. Keep in mind, in 1965 the 426 Hemi was introduced and it was listed at a whopping 425 horsepower. That number has been surpassed on cars used as daily drivers these days, and many consider 400 horsepower as “average” rather than impressive.

One of the problems with engines swaps is oftentimes the radiator that’s already in the car, even if it’s efficient enough, doesn’t have the proper hose positions to match up to the new engine. To cover the bases with LS swaps, Champion’s Double Pass radiator for the first generation Firebird and Camaro is just the ticket for that application.

The Champion radiator was a direct bolt in fit, directly replacing its wimpier counterpart right down to the internal transmission cooler. There were no modifications necessary, and Ed is now a happy camper.

The swap to the Champion radiator was a quick and easy swap, taking less than an hour to remove the old copper unit and bolt the aluminum unit into place. One advantage that Ed noticed was that now he has a brass petcock where the old method was to simply disconnect the lower hose and let it all flow out.

Champion Cooling Systems


All aluminum radiators

Part Numbers:

  • OE replacement: 370
  • Double pass: DP370
  • All aluminum construction
  • Fully tig welded
  • Fan shrouds and electric cooling fans available
After driving the car on a fairly warm day, Ed reported back to us that he is now seeing about 10 degrees cooler when cruising around town. He is getting a little bit of a climb at extended stop lights, and we’re planning an electric cooling fan upgrade, complete with a shroud, to help direct more of the air through the radiator and optimize efficiency.

Factory mechanical fans can often work well in these situations, however, with more power, and the original fan, it’s probably a good idea to step up to a more functional cooling fan setup on the old guy. We meant the Firebird, not Ed.

Ed’s Firebird was built to cruise, and he did all of the work himself, including the radiator installation. We asked what he thought about the radiator, and to provide us feedback if anything comes up that we need to take care of. Ed’s busy cruising, and last we heard he had a grin from ear to ear, and that’s saying something for old Ed.


While most radiators have two tanks, either upper and lower for down flow or side tanks for cross flow, the Double Pass radiator technically had three tanks and passes coolant through the core twice.

Double Pass Radiator

With the Double Pass radiator, the inlet and outlet are on the passenger’s side, so it would be necessary to utilize a different thermostat outlet that directs the upper hose to the passenger’s side. This option would provide even better cooling than the OE replacement. Matt Dawson at Champion Cooling Systems explained to us why the double Pass radiator would be a better choice where it can be installed.

Since the coolant will pass through the radiator taking the path of least resistance, that leaves some areas of the radiator where coolant won’t flow as much as the direct path from the inlet to the outlet. -Matt Dawson, Champion Cooling Systems

“All radiators have two tanks, and the coolant passes through the first tank, through the core, and into the second tank, then back to the engine. Since the coolant will pass through the radiator taking the path of least resistance, that leaves some areas of the radiator where coolant won’t flow as much as the direct path from the inlet to the outlet,” Dawson said.

“With the LS-style radiator, both inlet and outlet are mounted to the same tank, divided in the middle. Once the coolant enters the upper half of the tank, it crosses through the core to the driver’s side tank where it then drops to the lower half of the core,” he continued. “From there, the coolant flows a second time through the radiator, back to the lower half of the tank on the passenger’s side before the water pump pulls the water back into the engine.”

Because the core area is divided into two flow directions, more of the coolant will pass through the upper half, and then a second time through the lower half, which also provides more surface area keeping fluids cooler. By the time it gets to the bottom half, the fluid has already been cooled once.


For this stock application, the large, OE alternator did prove to be a little bit of an inconvenience, however, the radiator was a perfect fit and bolted directly to the core support. A smaller alternator might have give a little more room for the upper hose.

Why Use Champion Aluminum Radiators?

Aluminum radiators are beneficial for classic musclecars for a couple of reasons. For starters, aluminum is much lighter than its copper or brass counterparts, and most copper/brass radiators are brazed with lead, which is a major heat soak. Champion’s quality aluminum radiators are fully tig welded – not epoxied – with aluminum.

Champion also has its own, in-house fabrication facility, so when there is a case where the radiator needs to fit a custom application, its staff can take measurements from the customer and add mounting brackets or tabs on any radiator that it sells.

If you’re working on a classic with a completely modified front end, Champion can also create a new radiator specifically to those needs. In addition to fully tig welded radiators, Champion has its own line of fabricated aluminum shrouds and high-quality cooling fans, as well as cooling fan relay kits that function from a separate temperature sender.

You can find all of these products on the Champion Cooling Systems website, or you can reach out to the friendly staff to help get you into the right radiator, and cruising just a little bit cooler.


About the author

Michael Harding

Michael is a full time Power Automedia writer and automotive enthusiast who doesn’t discriminate. Although Mopar is in his blood, he loves any car that looks great and drives even faster.
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