22 or 26 inch radiator

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Mojoe9955

Mojoe9955

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I have a choice between a 22 and 26 inch radiator for my 318 Duster project. Same price, $50. The 22 is 40 miles away and the 26 is 140 away. Both guys say they came out of their Dusters. I'm reading up and finding that early 318 cars have the 22 and the later cars with 360's have the 26."
i have a 70 Demon 6, 70 Duster 318 and a supposed 74 Duster 360 yet all the openings measure the same 22.5" wide. The Demon has a 22 in, the 70 Duster has a 26" screwed in with some self tapping sheet screws which doesn't seem right some I'm thinking it should be a 22. The 74 looks like even though the opening is the same size it looks like it has factory mounts for either one.
Long story I know... I'm putting a 318 in the 74 and am just wondering if the 26 from the 70 is a better choice in the 74 and put the "new" 22 in the 70? Or...the "new" 26 in the 74?
 
I believe the 26" radiators started in '73 or so- but not all of them got them. Slants and non-ac 318s still got the 22s.
The best way to tell what it originally came with is to measure the opening in the radiator support.
A 26" rad will physically fit the 22" support, it just may not have the wider attachment points for the 26. And running the 26 on a 22 support is kind of an exercise in futility, since you are blocking off a good chunk of surface area on the bigger radiator- and thus not really gaining anything. Unless, of course, you open up the radiator support to the 26" dimensions.
 
It looks to me like it has provisions for both. I just spoke with the guy who has the 26 and he said it came out of a 73.
The next thing would be the fan size. I think the 22, at least in my 6 has a 4 blade 17.5" dia fan. While the mash-up with what looks like the correct 26 for the 73 and up in my 70 has a 7 blade 17.5 diameter fan. While the opening is smaller the wind on the front has a cooling effect and back side is fully exposed to the fan which I believe does the brunt of the work. I assume the extra coolant has an effect as well. While I'm looking things over I see its missing the coolant overflow canister on the 70 while it is present on the 72 and 74....hmmm.
 
All 1974 duster 360's had a radiator opening that was 26 inches. Also 1974 Duster's with 318 engine and AC had 26 inch opening.
 
It’s odd that your ‘74 Duster has a 22.5” opening if it was a real 360 Duster. Sounds like it’s not. What’s the 5 digit of the VIN on the 74 Duster? Is it a ‘C’ or a ‘G’ or an ‘L’?
 
The previous owner said that the previous owner said it was a 360 car. I didn't matter to me what was in it as I'm not a numbers matching or has to be correct kind of guy. It was a nice project, with good body that already had a lot of work done already and good deal so I bought it.
Looking at the vin the 5th character is a C.
I'm going to look into that.
Thanks
 
Mojoe9955 said:
i have a 70 Demon 6
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'70 Demon? My Demon has been made in Sept.1970, but it's a '71 model.

Anyway... when I purchased the car, the original radiator was history, so I looked for an OEM radiator and found a 1971 26 in. (out of an E-body). P/N 3443970.
Got it rebuilt and now it's in the car. So, I can say "a 26 inches rad fits a slant 6/318 22" rad support" and the cooling is just perfect...:)

20230627_170016.jpg
 
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I did look up the vin and the car actually came with a Slant 6. As I said, Im not hung up on being correct, I probably ought to be paying better attention. At $50 each I might just pick up both. They are supposed to "not leak" but it was also supposed to have "had a 360". Whatever happens either one will work with the 318 that will be going in the car.
Thanks
 
I hope the old rad. prove to be good. I have never had a lot of luck with the old ones!! Seemed like the were OK back in the 80s and 90s!! :BangHead:
 
A 26” radiator in a 22” opening probably doesn’t cool much better than a 22” radiator in a 22” opening. I’d try to find a stock 3 core 22” radiator and shroud and go with that. That’s what I ran in my 440 ‘cuda and it rarely ran over 185 degrees.
 
I put a 26" in my Swinger. It came with the small radiator but the dealer installed a/c didn't get a larger upgrade. No overheating issues now.
 
The 22 inch shroud has 4 small corners, less than the size of your hand, beyond the size of the core and opening. Very little additional core coverage. There just isn't much gained with that. The 26-inch radiator with basically same diameter fan gains much more from additional core size and even more with a shroud. If I could get my hands on an OEM 26-inch radiator, clutch fan and the shroud, I would happily sawzall/widen the opening of my 67 fish to utilize it.
 
dodgedifferent2 said:
I say make the 26 work because it will have more surface area to cool when you hot rod it
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A 26” rad with a 22” support opening means there 2” on each side that is blocked from any air flow.

Someone else mentioned it already but regardless which size you out in any car, make sure each one has a shroud.
 
I just used a cut off wheel and widened the opening to accommodate the 26" radiator
 
Anyone that says a 26” radiator behind a 22” radiator support isn’t much benefit doesn’t know what they’re talking about.

The amount of the 26” core that’s obstructed by the slightly smaller opening is pretty minimal. It’s true, the cars that originally came with 26” radiators had a larger opening in the support, but the difference isn’t that much. And it’s not like the core is pressed against the support either, the extra core that’s “behind” the support opening still is exposed to air, so it still works to dissipate more heat than the smaller core.

And more importantly, when does the car run hottest? The biggest cooling issues with these cars are usually at idle or slow speed, when the fan is doing all the work of moving air. If the fan is doing the work, and you’re running the proper fan shroud on the radiator, the fan will pull air across the entire core. By not opening up the radiator support to the full core width all you do is obstruct a little bit of the core when the car is moving at speed, when the speed of the car is pushing air through the grille and the radiator opening. These cars usually don’t have any issue cooling at speed.

My ‘74 came with a 22” radiator, I run a 26” now with an electric fan set up and the original radiator support opening. At speed my fans never run. At all. The smaller opening moves more than enough air at speed to cool the car to the thermostat temp. And at low speed or idle the fans pull air across the entire 26” core because of the 26” wide shroud.

You will have to add the mounting points for the 26” radiator if the car was set up for the 22” because the mounts for the 26” radiator are wider, but that’s all you need to do. Opening up the hole in the radiator support will help move more air at speed, but it’s a small difference.

This is a picture of the 22” radiator support in my car with the 26” radiator, the mounts for both radiators are marked, as well as the full width opening for the 26” radiator support…
IMG_4945.jpeg


And this is a factory 26” support
IMG_4946.jpeg
 
72bluNblu said:
Anyone that says a 26” radiator behind a 22” radiator support isn’t much benefit doesn’t know what they’re talking about.

The amount of the 26” core that’s obstructed by the slightly smaller opening is pretty minimal. It’s true, the cars that originally came with 26” radiators had a larger opening in the support, but the difference isn’t that much. And it’s not like the core is pressed against the support either, the extra core that’s “behind” the support opening still is exposed to air, so it still works to dissipate more heat than the smaller core.

And more importantly, when does the car run hottest? The biggest cooling issues with these cars are usually at idle or slow speed, when the fan is doing all the work of moving air. If the fan is doing the work, and you’re running the proper fan shroud on the radiator, the fan will pull air across the entire core. By not opening up the radiator support to the full core width all you do is obstruct a little bit of the core when the car is moving at speed, when the speed of the car is pushing air through the grille and the radiator opening. These cars usually don’t have any issue cooling at speed.

My ‘74 came with a 22” radiator, I run a 26” now with an electric fan set up and the original radiator support opening. At speed my fans never run. At all. The smaller opening moves more than enough air at speed to cool the car to the thermostat temp. And at low speed or idle the fans pull air across the entire 26” core because of the 26” wide shroud.

You will have to add the mounting points for the 26” radiator if the car was set up for the 22” because the mounts for the 26” radiator are wider, but that’s all you need to do. Opening up the hole in the radiator support will help move more air at speed, but it’s a small difference.

This is a picture of the 22” radiator support in my car with the 26” radiator, the mounts for both radiators are marked, as well as the full width opening for the 26” radiator support…
View attachment 1716120457

And this is a factory 26” support
View attachment 1716120458
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I tend to agree. Also, even though I'm not a "correct or "numbers" guy, it doesn't make sense to start hacking up the car in case I pass it on to someone who is.
 
Mojoe9955 said:
I tend to agree. Also, even though I'm not a "correct or "numbers" guy, it doesn't make sense to start hacking up the car in case I pass it on to someone who is.
Click to expand...

Yeah the larger radiator still adds surface area for cooling, and still adds more coolant capacity which also improves cooling. Sure, if you open up the radiator support to the full width you will get additional cooling at speed than if you don't, but realistically that's not when you need additional cooling on most of these cars. With a fan and shroud installed you'll still pull air across the entire core at idle and low speeds, which means you're using the entire core even if there's some of the edge that is obstructed from direct flow from the front.

On the 22" radiator supports it's also very easy to see where the 26" opening would be, because the lower part of the support that's welded on is the same for both supports. So, you can see that the corners on the lower part of the support are back from the inner edges on the 22", and inline with the edges of the opening on the 26" supports.
 
Mark Merrill said:
I put a 26" aluminum in my 73 318 Dart Sport with X heads and it runs too cool now. Not a bad problem to have.
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In certain conditions 'too cool' could be a bad problem to have. For 35 years my dad would drive whatever vehicle he owned nearly 5 miles from home drieway to textile mill parking lot and back again 8 hours later.
At those lower temp engine areas like sheet metal rocker covers and top of the heads, the paraffin in yesterdays motor oils would set up like black candle wax everywhere. Then we would take the vehicle on a longer drive and the stuff would get hot and fall away, eventually clogging oil returns and even the pickup in the pan. I don't recall how many times he would have to pay someone to desludge an engine.
Quakerstate brand got a bad reputation during those times mostly for this issue.
Even though most mfgrs went to 195-degree thermostats we still saw the same sludge buildup in Fords thanks to their Havoline oil.
 
RedFish said:
In certain conditions 'too cool' could be a bad problem to have. For 35 years my dad would drive whatever vehicle he owned nearly 5 miles from home drieway to textile mill parking lot and back again 8 hours later.
At those lower temp engine areas like sheet metal rocker covers and top of the heads, the paraffin in yesterdays motor oils would set up like black candle wax everywhere. Then we would take the vehicle on a longer drive and the stuff would get hot and fall away, eventually clogging oil returns and even the pickup in the pan. I don't recall how many times he would have to pay someone to desludge an engine.
Quakerstate brand got a bad reputation during those times mostly for this issue.
Even though most mfgrs went to 195-degree thermostats we still saw the same sludge buildup in Fords thanks to their Havoline oil.
Click to expand...
Thank you but I will get to 190 to 200 degrees so I can monitor the air fuel ratio meter more accurately. Then the Holley tuning fun continues.
 
RedFish said:
In certain conditions 'too cool' could be a bad problem to have. For 35 years my dad would drive whatever vehicle he owned nearly 5 miles from home drieway to textile mill parking lot and back again 8 hours later.
At those lower temp engine areas like sheet metal rocker covers and top of the heads, the paraffin in yesterdays motor oils would set up like black candle wax everywhere. Then we would take the vehicle on a longer drive and the stuff would get hot and fall away, eventually clogging oil returns and even the pickup in the pan. I don't recall how many times he would have to pay someone to desludge an engine.
Quakerstate brand got a bad reputation during those times mostly for this issue.
Even though most mfgrs went to 195-degree thermostats we still saw the same sludge buildup in Fords thanks to their Havoline oil.
Click to expand...
When I first became a mechanic ,this was a common problem in most vehicles. Oils had very little detergents in them then if any.
 
I am a firm believer in putting in the biggest frigging radiator that will fit between the frame rails. Me? 100% the 26". My little car with no fenderwells uses a 31" a/c dually radiator.
 
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