1972 Chevrolet Corvette Scarlett Project Car - Cooling System and Hydroboost

Going With The Flow

Jeremy D. Clough Aug 19, 2014 0 Comment(s)
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Last time we wrenched on Project Scarlett we installed a sweet fuel system. But, anyone who’s been deep into an engine swap will realize fuel isn’t the only plumbing involved in putting a hotter motor under the hood. In addition to giving it something to drink, you’ve got to cool the beast, which necessitates a more robust cooling system. In the case of LS engine this also includes making provision for the steam lines that cross from one cylinder bank to the other.

In our case, we used a heavy-duty aluminum radiator from DeWitts that came equipped with a pair of SPAL electric fans, as well as a fitting for the steam line from the front of the engine. Although the radiator was designed for LS swaps, unfortunately ours had to go back home a couple of times to get the inlets and outlets oriented to clear the control arms, a frustration that unfortunately fit with the “everything has to be done three times” rule Tray and I discovered early on.

Since we were changing to a different kind of radiator, we bolted it in place in a new big-block core support provided by Corvette Central, along with the upper clamps and rubber cushions that hold it firmly in place. We also purchased the foam seals needed to keep air flowing through the radiator instead of between the radiator and core support. Since there was no way factory radiator hoses were going to fit, Tray bent a piece of thin metal rod to the size and shape we needed, and we adjourned to the local O’Reilly. When he was asked by the counter guy what car it was going in Tray simply said “It doesn’t exist,” since an LS-powered C3 wasn’t going to show up in the computer. He was kind enough to let us peruse their hose selection in the back until we found 1.50-inch ID hoses that were close enough to work.

Another thing we realized wouldn’t be a stock item was the radiator overflow bottle. Required for track work, and just a general good idea, an overflow bottle (aka “puke tank,”) gives the radiator some place for the overflow to go when the coolant expands beyond the radiator’s capacity. Preferably, it should also let the coolant flow back into the radiator when it cools. Unfortunately, we couldn’t readily locate an aftermarket one that would fit in our limited space confines and opted not to modify a stock one, so we made one from aluminum. Once it was done and mounted in place properly, we pulled it off to have it polished.

As a separate system that needed to be plumbed, we also had a hydroboost system donated by Hydratech. The factory power brake booster that operates off engine vacuum can be troublesome in applications like ours where a hotter cam may not make the vacuum required to keep everything working. The Hydratech system solves this by using fluid shunted off the power steering pump to provide the power assist for the brakes. Known for giving a firm pedal feel, we expect it to make the Wilwood brake system, with its six-piston front and four- piston rear calipers, feel even better than it already does.

Dewitts Radiator 2/22

1. Not only will our 600-plus-hp LS benefit from the added cooling capacity of the aluminum DeWitts radiator with its dual SPAL electric fans, the DeWitts unit also has the proper fitting for an LS steam line. As it turned out, due to the limited clearance, we had to remove the fans to get the radiator in place, then locate and mount the fans.

Dewitts Radiator Fittings 3/22

2. Here’s the top of our DeWitts radiator showing the fittings for the upper radiator hose, overflow, and LS steam line, which is the small nipple with the black cap. This is the modified radiator since ours had to go back to have the upper and lower hose outlets relocated. In their original orientation we had clearance issues with the control arms.

Corvette Central Radiator Support 4/22

3. We seated our radiator in a new core support provided by Corvette Central, which is shown here (front) compared with the factory one we pulled out. While there are several different configurations for the core support, we used a big-block support to pair with the new radiator. Shipping these is a challenge since UPS bent ours twice.

Radiator Lower Mounting Brackets 5/22

4. While the lower mounting brackets are on the bottom of the radiator core support, the upper ones comes separately, and were provided by Corvette Central. Both the upper and lower will need the rubber cushions that lock into place in the brackets, and you’ll also need the foam seals that go between the radiator and core support.

Rusted Screws 6/22

5. Another example of why it’s a good idea to take a hard look at your cooling system: the parts, such as this mounting screw tend to rust. We replaced all the hardware with new stainless fasteners.




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