Project Ramp Truck: Improving Our Cooling System

Update by Tim Suddard to the Ford F-350 Ramp Truck project car
Jun 24, 2019

As a quick reminder, our truck is a 1973 Ford F 350 ramp truck (or car hauler) that we found in a barn a few years back. We restored it and then modified this truck for our racing efforts on the pages of Grassroots Motorsports.

Once we were comfortable using the truck with its rebuilt engine and got around to using it more and more, winter turned to spring and then spring to summer. It ran fine during the cooler months, but once summer hit, we noticed our ramp truck started to run hot, especially when we were stopped in traffic and running the air conditioning. Our initial fix was to install an auxiliary cooling fan that came on when the A/C was running. This helped make the A/C a bit more effective, but we were still running warmer than we wanted, especially when we got caught in traffic. We had never messed with the original cooling system and decided that with our added displacement, the added A/C ,and the fact we were regularly driving this thing at (or above) highway speeds, the final thing we needed to modernize was our truck’s cooling system.

Generally, when we have a cooling question, the first people we call is Griffin. They have helped us make everything from our dedicated race cars to our Sunbeam Tiger run cool, and though we figured an F 350 might not be directly in their wheelhouse, we hoped they might be able to make suggestions, or lead us down the right path.

We were surprised, however, when Griffin’s marketing director; Steve Beebe instantly sent us a technical diagram of an aluminum radiator, with the exact same dimensions as our radiator, complete with the correct mounting attachment points.

Making this an even easier decision for us, the drawing showed an aluminum fan shroud with pass through flaps, twin 12” Spal cooling fans and the correct temp sensor and wiring harness. As an added bonus, this Griffin High Performance Combo unit only weighs about 35 pounds, which is half what the radiator in our truck weighed.

Apparently, this was not the first time Griffin had ever been asked to build a radiator for an old Ford F 350. To whomever came before us: You have our thanks.

The Griffin radiator is designed to not just replace the radiator in our truck, but it also comes with their MegaCool radiator tubes that are said to more effectively dissipate heat. Also, Griffin generally builds their radiators with additional rows of tubes, versus the stock radiator they are replacing. Efficiency is paramount.

The Spal fans are rated at 1722cfm each, and with the slickly built shroud, were a great improvement over the stock mechanical fan we were using.

Priced at $1397.86, and considering what you are getting, how you need to do zero engineering and how immense this radiator is, we thought the whole thing was a pretty good deal. In comparison, a new stock radiator was about $500 and that does not include the fan shroud nor the two electric fans.

New versus Old

Installation was very easy. The radiator’s light weight made bolting it in much easier than the stock radiator and the mounting tabs matched the stock location perfectly.

Fan wiring is straight forward as well, as the kits comes with detailed instructions, the relays you need, and a 185-degree temp sensor that you need to mount into the intake manifold.

Once installed, the fans ran quietly. And technically-speaking, without an engine driven fan sucking up precious power, we should pick up a few extra ponies.

When it was all said and done, our truck no longer has any cooling issues under any circumstances: It’s as cool as a cucumber, at least a cucumber that can haul a car.

Once again, look for us at a race track near you.


Griffins Ten Commadments For Maximum Cooling

1. Thou shall make room for an adequate cooling system in the design of your engine compartment.
First things first. When planning your performance vehicle, remember that you're building it to drive, not to sit and steam. Plan adequate space for the cooling system including the radiator, fan, shroud, over flow tank and mounting brackets. Talk with a cooling specialist to help you size the system for your vehicle, engine and driving habits. Consider the investment compared to the total cost of the car.

2. Thou shall shroud thy radiator when using a fan.
Fans move air through the radiator assisting in cooling the engine. A fan without a shroud is better than no fan. But, consider this. At idle or cruising speeds, you need the entire cooling system working at its optimum. An unshrouded fan is moving air through only the portion of the radiator equal to the surface area of the fan. For example, on a '32 Ford, the area of a 15.50" fan is about 189 sq. in.; the core of the radiator is approximately 371 sq. in. This means that almost 49% of the unshrouded radiator is not receiving any benefits of the fan. Shrouding your radiator lets the fan pull air through the entire core.

3. Thou shall use an electric fan.
Rule of thumb. Only choose a mechanical fan over an electric fan if it's your farm tractor. An electric fan is preferred because when you need a fan the most (at idle or cruising speeds) an electric fan is delivering maximum air independent of engine RPM's. Fans that move 2000-2300 CFM's are worth the investment. Preference should be given to a "pull" vs. a "push" fan. Mounted on the engine side of the radiator, a pull fan does not interfere with air flow at highway speeds. All shrouded fans should be on the engine side of the radiator.

4. Thou shall consider airflow or how a radiator cools.
Without adequate air flow, a radiator is just a reservoir for hot water. Coolant transfers heat to the tubes; the tubes transfer heat to the fins; air moving through the fins dissipates the heat from the radiator. You need sufficient openings to the radiator that channel adequate air to the entire surface of the radiator. You must have a radiator design that allows the air to pass effectively through the radiator (wider and taller is better than thicker). You must consider how the heat will be evacuated from the engine compartment.

5. Thou shall use the proper water pump pulley ratio.
To obtain the maximum operating efficiency rate for your water pump at highway speeds, you should overdrive the pump by 30-35%. Check your pulley selection. Most after market pulleys are a 1:1 ratio. For a 30-35% overdrive, the crank pulley should be approximately 7 7/8" and the water pump pulley approximately 5 3/4". This overdrive provides proper coolant flow from the engine and through the radiator.

6. Thou shall consider the effects of the pressure cap.
The higher rated the pressure cap, the hotter the water has to get to boil. One pound of pressure raises the boiling temperature 3°F. A 16-pound cap raises the boiling point to 268°F. If your engine is designed to run at 200°F, a 14-16-pound cap should be sufficient. Running a higher pressure cap to prevent boil over is putting a band aid on another problem that needs to be fixed. Higher operating pressure places additional stress on the entire engine system and increases the potential of hoses bursting and possible injury.

7. Thou shall understand the operating temperatures of today's modern engines.
All engines have "normal" operating temperatures. Running engine temperatures well above or below recommended temperatures could cause damage. Most of today's engines operate in the 180°-210°F range. Pollution laws, new oil blends and higher combustion gasoline have forced engine design changes that have increased operating temperatures over the past decade. Consider your engine's normal operating temperatures when selecting your radiator's cooling capacity.

8. Thou shall always use a thermostat.
The thermostat controls engine coolant temperature. It stops the flow of coolant through the radiator until the coolant reaches the thermostat's preset temperature. Operating your engine within its temperature parameters reduces wear, helps control emissions and turns any moisture in the crankcase to steam where it is removed by the PCV system. Select the right thermostat for your engine's operating temperature range.

9. Thou shall protect thy cooling system with recommended coolant.
It is essential to use a premium coolant that protects the radiator, other metal parts and seals. Today's coolants are a scientific blend that normally includes water wetter and corrosion inhibitors. Use of a coolant that contains no silicate is recommended. Silicate is an abrasive and can cause gel formation and water pump failure. A 50/50 mix of coolant and distilled water provides the best overall cooling efficiency. Proper maintenance (regular flushing and changing of coolant) will extend the life of your system.

10. Thou shall spend thy money wisely.
If you are having cooling problems, begin by looking at the least expensive fixes first. 1) Add an electric fan. 2) Shroud your fan. 3) Check your belts and hoses. Slipping belts or collapsed hoses mean trouble. 4) Check your radiator cap. 5) Flush and refill with premium coolant. 6) Use the proper thermostat. 7) Clean the radiator of foreign materials. 8) Overdrive the water pump 20-30%. 9) Check your water pump. Should cooling problems persist, it may be time for a new performance radiator from Griffin. Call the Griffin Customer Service Department at 1-800-722-3723 for assistance in selecting the correct radiator for your requirements.


** WARNING: Improper wiring can cause electrolysis and destroy the radiator. Please make sure radiator is not used as a ground. **


Join Free Join our community to easily find more project updates.
View comments on the GRM forums
Vigo MegaDork
6/24/19 10:54 a.m.

That's a nice setup and the somewhat silly cost of the stock radiator sure helps sell the upgrade! 

vettelocke New Reader
6/25/19 7:49 a.m.

And the scrap value of the copper in the OEM makes the deal even sweeter!

Or did you find a way to put it into a Miata that was supercharged?

Sponsored by

Falken Tires


Our Preferred Partners