When my 2 core radiator took a shit, I replaced it with a 4 core American made for only 200 scheckles....
With a good radiator and all things being equal there shouldn't be much difference,I have a 350 Chevy in my old Deuce sedan with a Walker radiator and a 17" mechanical fan and in bumper to bumper traffic never runs over 200 degrees. I also have a 302 Ford in the Ranch Wagon which as a Walker radiator, a identical 17" mechanical fan and it too never goes past 200 degrees in sit still bumper to bumper traffic. HRP
I have never had a problem with either one. The same radiator that cools a small block mustang cools most of the SBC powered model As on this board. So I would have to guess that they are pretty close to the same.
Sort of a loaded question. All other things being equal, heat rejection to the coolant is a function of fuel rate. The Chevy 350 has a larger displacement, so, at rated speed and power, it will burn more fuel at the same a/f ratio, make more power, and burn more fuel, and send more heat to the coolant. Problem is, except for brief periods of time, you never run at rated speed and load, unless you are in a medium duty truck. Even at part load, though, both engines run similar a/f ratios, so the one that pumps less air (or burns less fuel ) should reject less heat. The SBF traditionally has a longer water pump, so the fan will be closer to the radiator, in relation to the front face of the block, and there will be more room to flow hot air out the bottom of the car. That increased air flow takes more Btus away from the coolant, reducing the water temp.
Both are easy to cool in most cases. Are you building something with little or no grill? Whats the vehicle or limitations?
The car companies designed both to run cool in all condition's stock. You vary from stock and everything changes. We cooled a limited late model dirt track car for 75 laps getting air to the radiator through a 7in by 14 inch hole. Behind that hole was an aluminum shroud that forced all the air through the radiator and we had a Speedway solid fan belt driven by the water pump. We were looking for 195- 205 degree optimum water temp. That was a 350 turning 7500 plus rpm's twice a lap in a 90 plus degree temp. Air flow through the radiator , not over or around the sides make a huge difference. 302 Ford would cool the same .
Cooling is primarily a function of power produced and overall engine efficiency. a 500 hp 302 will be much harder to cool then a 300 hp 350, given the same radiator and coolant flow rates (and assuming the 302 block doesn't split in half at that power level....) The radiator needs to be able to reject the same or more heat energy from the coolant into the air then the engine it is cooling injects into the coolant. Cubic inches has very little to do with it except from the very, very general rule that more displacement produces more power.
If you get out of bed on the left, the Ford will cool better, if you get out of bed on the right, the Chevy will cool better.
the amount of cooling needed is a direct relationship to the amount of energy created with a ever so slight variance in mechanical efficiency.
I recently had Pete and Jakes build me a chassis. When I was spec'ing things out and we were talking about engine location/firewall setback/radiator location and choices I asked Jason about the need to run a thick or thin Walker radiator. He said the thinner one would buy me a couple inches room for the longer Ford. I told him my concerns on cooling problems and we walked into the showroom where the California Kid and Jake's Coupe both sit. He said the California Kid always ran cooler then Jake's Coupe. No matter what they did. He's since seen it with several other cars, too. He said all things being equal, the Ford can get by with less radiator than the Chevy. I took that as gospel, they've worked with a lot of builders. SPark
If you think about it from a theory standpoint, the bigger engine will potentially make more heat at full power, assuming both are about the same relative hp/cu inch level. But rarely do you operate at that max power for long period of time. Most driving conditions, either engine will make the low power required to maintain the speed or the modest acceleration. That takes basically the same amount of power from either engine. So it is also approximately the same cooling load. One thing that could make a difference is airflow in the engine compartment. A SBC is shorther length and wider than a SBF. So in a cramped compartment, the SBF may allow a bit easier air *from* the radiator to exit, being more room and longer on the sides of the engine vs the engine compartment. This would in turn make it seem the SBF is easier to cool. But then my opinion is to run what you like and then optimize the cooling within the limits you have.
The thing that no one is taking into account is the water jacket design and coolant flow. Everyone's theory on displacement is basically sound until you get to the fact that both engines are not identical in any way shape or form. Case in point, we have 350 Chevrolet as an option. Now are we considering an off the assembly line 350 or a destroked 400 Chevy. The destroked 400 is actually a better engine from a mechanic's/performance point of view but it is way harder to cool that the off the assembly line GM 350. Same cubes different coolant flow. Next one must take into consideration the amount of coolant flow. I use a flow cooler water pump on my 355 for example. When I bought the water pump the claim was 15 degrees cooler than a stock pump. It was a valid claim. There is still a variable or two that I won't go into because the water is already so muddy that the salvage divers cannot find a thing.
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