Has anyone tried making the hole in their radiator housing larger to fit a larger radiator?

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harrisonm

harrisonm

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When I bought my 69 Barracuda about 33 years ago, it had a pretty good sized radiator in it. I assumed it was a 22" out of a B or E model. It did JUST fit from side to side, but about 1.5-2" of the core was blocked on each side. I stripped the entire car down to bare metal both times I painted it (once about 30 years ago, and again about 10 years ago). My car runs cool enough, but on a hot day with the AC on, it gets pretty warm. I have a really good radiator with the proper fan housing and blade. Both times when I painted it, I considered increasing the hole size for a larger (22" I think) radiator. I know the radiator support is a structural piece, but it would be easy enough to enlarge the hole and bolster the strength. I decided not to both times. I wonder if anybody else has actually enlarged the hole.
Before anybody asks, the 340 is at about 375 HP, the block was hot tanked, I flushed the CRAP out of the block several years ago with pretty much every orifice open, and after a few minutes I was getting clear water. I have a nice Griffin exact fit radiator that is "Guaranteed" up to 600 HP. Don't get me wrong, it has never overflowed, but on a hot day with the AC going the temp gauge is almost pegged, and the temp at the thermostat housing is about 220. I just live with it.
 
Did it on my 76 D100 Truck when going from a slant 6 to a 318 V8 factory truck radiator.

Cut out 1 1/2" on the driver's side of the radiator core support so the opening would fit the larger radiator.

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When I built my swinger I swapped in a radiator support from a 26" radiator car. If I recall, only one side is different.
 
Yup, I did on my 73 big block challenger and my 408 Dart. Some of the 73 and up a-bodies had 26“ radiators from the factory when they had AC.
 
You can put the biggest core size radiator in an A body (early or late) and the size of the hole on the core support does not matter. The core support hole does not have to be the same size as the radiator core. As long as the majority of the core sees air flow, that's all that matters. You won't see an appreciable difference from an inch or two of the core blocked on each side.
 
I run a 22 inch 3 row copper core and never had a cooling problem. Big or small block. Does it get hot cruising on the highway or idling in town?
 
If it was a 340 it definitely came with a 22'' from the factory.
 
I did. But I've got a side tank radiator in my race car. 66 Valiant. Now the radiator tanks are about 1/8 of an inch from frame rail to frame rail and the core is completely open. Old set up had about 1.5 inches of core covered and both tanks behind the support. Can't tell you if it works better till next race season. I'm sure it will. I like the suggestion of using a later 26 core support. Keep your original. Good luck.

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I opened up the core support on my 62 savoy, about four inches, on one side only, from the stock slant six 22" to a 26 (or is it 28) Cordoba big block high efficiency (more fins per inch than normal) radiator, and matching shroud.
It used the stock 62 mount holes on one side, drilled a couple more on the opened up side.
Currently using radiator and shroud, transcooler inside shroud, flex fan that moves a bunch of air, and a ten inch electric pusher (to cool between rounds during hot laps).

...and I have no idea why it started out in italics, then changed back to normal, lol.
 
harrisonm said:
When I bought my 69 Barracuda about 33 years ago, it had a pretty good sized radiator in it. I assumed it was a 22" out of a B or E model. It did JUST fit from side to side, but about 1.5-2" of the core was blocked on each side. I stripped the entire car down to bare metal both times I painted it (once about 30 years ago, and again about 10 years ago). My car runs cool enough, but on a hot day with the AC on, it gets pretty warm. I have a really good radiator with the proper fan housing and blade. Both times when I painted it, I considered increasing the hole size for a larger (22" I think) radiator. I know the radiator support is a structural piece, but it would be easy enough to enlarge the hole and bolster the strength. I decided not to both times. I wonder if anybody else has actually enlarged the hole.
Before anybody asks, the 340 is at about 375 HP, the block was hot tanked, I flushed the CRAP out of the block several years ago with pretty much every orifice open, and after a few minutes I was getting clear water. I have a nice Griffin exact fit radiator that is "Guaranteed" up to 600 HP. Don't get me wrong, it has never overflowed, but on a hot day with the AC going the temp gauge is almost pegged, and the temp at the thermostat housing is about 220. I just live with it.
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A few questions Harrisonm,

1. Is the fan shroud sealed around its perimeter?

2. What fan assembly are you using?

3. What water pump?

4. How close to the rad is your fan blade?

5. Is it a 3 core radiator?
 
I did this to my 67 Dart. I opened the hole in the core support a little and lowered the bottom of the support to fit a b body radiator in the car and make it look like it's supposed to be there. The hole was only opened an inch or two on each side and I doubt it actually does anything.

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67Dart440GT said:
I did this to my 67 Dart. I opened the hole in the core support a little and lowered the bottom of the support to fit a b body radiator in the car and make it look like it's supposed to be there. The hole was only opened an inch or two on each side and I doubt it actually does anything.
Click to expand...
Hey I did near the exact same thing on my 67. I thought mine was a 26" rad from an E body. I know I got it from champion.

I had to swap rads when I went big block. The dinky 22" looks tiny now.
 
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