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Discussion Starter · #1 ·
Im new to the site but here it goes I have a 1969 Chevelle Malibu convertible SS close
Has the original small block radiator in it dropped in a high-performance small block Chevy 400/408
Running 180° thermostat what car was running hot around 210
I decided to go with the aluminum radiator full size 2 row core from from Cold case radiators 2 row. Wanna try to do it right the first time I’ve read through the site for which shroud to pick but I’m still a little lost because I have a small block not a big block but do you have the bigger radiator.
should I go with the 71 to 72 shroud and I do have the 772 fan and Hayden clutch don’t know if anyone has the same set up?
Any guidance would be appreciated
 

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Radiator requirements goes by HP not engine size within reason. My L79 327/350 all cast iron runs steady at 180, maybe a touch higher with the AC on in traffic on a hot day. I am running stock HD cooling (28 inch wide radiator and correct core support) 5 blade fan, Hayden clutch and stock shroud. My fan is half in and half out the shroud. If you currently have no shroud today that is a big part of your problem. Also lean mixture or a vacuum leak can cause extra heat as well as incorrect timing. I am using a dual row 1.25 inch Cold Case radiator as well.
 

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Discussion Starter · #5 ·
Post a picture of the core support. The area behind the grill.
I’m just getting everything in place to do the change out with the radiator I know I have to open up the radiator support it has that area of about 5 inches from the stamped radiator support that needs to be removed
I’m just getting everything in place to do the change out with the radiator I know I have to open up the radiator support it has that area of about 5 inches from the stamped radiator support that needs to be removed
I was just curious about the shroud that would fit with the new oversize radiator I saw on the forum that some guys were saying that a 71 to 72 trout fits better anyone have a part number for that?
Timing and vacuum all seem good on the car I think it’s that I was just running that old 52 year old radiator and in traffic it was heating up a little.
I would assume the bottom hose might fit OK but the top radiator hose would have to be longer and I don’t know if anyone has a part number for that either any help I really appreciate it trying to learn by everybody else’s mistakes 😇
 

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400s run hotter then other sbc's, Just because your used to a lower temp with a different motor, doesn't mean your 400 is running hot.
Make sure your cooling system is in good working order and don't worry about it.
 

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I’m just getting everything in place to do the change out with the radiator I know I have to open up the radiator support it has that area of about 5 inches from the stamped radiator support that needs to be removed
I’m just getting everything in place to do the change out with the radiator I know I have to open up the radiator support it has that area of about 5 inches from the stamped radiator support that needs to be removed
I was just curious about the shroud that would fit with the new oversize radiator I saw on the forum that some guys were saying that a 71 to 72 trout fits better anyone have a part number for that?
Timing and vacuum all seem good on the car I think it’s that I was just running that old 52 year old radiator and in traffic it was heating up a little.
I would assume the bottom hose might fit OK but the top radiator hose would have to be longer and I don’t know if anyone has a part number for that either any help I really appreciate it trying to learn by everybody else’s mistakes 😇
Capt Casey just went through the radiator support and hoses with his HD cooled 68 SBC so maybe he has the numbers. He also bought but didn't use after market shroud. He has details. However he is using a stock wide core radiator. I posted this pic yesterday for another post but here it is again plus two more. Ignore the in/out of the fan blades since the core is not bolted to the fenders.

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Discussion Starter · #8 ·
Capt Casey just went through the radiator support and hoses with his HD cooled 68 SBC so maybe he has the numbers. He also bought but didn't use after market shroud. He has details. However he is using a stock wide core radiator. I posted this pic yesterday for another post but here it is again plus two more. Ignore the in/out of the fan blades since the core is not bolted to the fenders.

Bill
View attachment 715378 View attachment 715379 View attachment 715380
That the same set up I have with the small block but again I saw guys post that shroud that works was from a 71-72 chevelle just wondering about a part number ? And hopefully my fan set up will work with that shroud and less I have to increase the fan diameter?
 

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That the same set up I have with the small block but again I saw guys post that shroud that works was from a 71-72 chevelle just wondering about a part number ? And hopefully my fan set up will work with that shroud and less I have to increase the fan diameter?
My setup and yours if the same should work with no issues. The 71 and 72 is larger as is the fan, I believe its 19 inches versing our 17.5 inch. Opening up the core should help.
 

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Im new to the site but here it goes I have a 1969 Chevelle Malibu convertible SS close
Has the original small block radiator in it dropped in a high-performance small block Chevy 400/408
Running 180° thermostat what car was running hot around 210
I decided to go with the aluminum radiator full size 2 row core from from Cold case radiators 2 row. Wanna try to do it right the first time I’ve read through the site for which shroud to pick but I’m still a little lost because I have a small block not a big block but do you have the bigger radiator.
should I go with the 71 to 72 shroud and I do have the 772 fan and Hayden clutch don’t know if anyone has the same set up?
Any guidance would be appreciated
You should get the Shroud for the Size of the Core in your Rad AND the type of Engine eg. SBC or BBC
because the Depth of a SBC Shroud is Different than a BBC Shroud
eg. if the Alum Rad Core is 28" Wide by ??" High then get the Shroud that fits those Measurements
and the Fan that fits the Shroud Opening less a Inch or 2
GrdUp is a Good Source of info of what you need // then you can buy it where ever
Ground Up - SS396.com: Product Search
EG. 1. 1969-1970 Chevelle Small Block Fan Shroud for Large Core, 4 Hole Top Plate for a 31" Wide Xcross Flow Rad Core
at the Bottom of that Item's Page there is a List of Related Parts for it
........2. 1969-1970 Chevelle Small Block Fan Shroud for 24 Inch Small Core for a 24" Wide Xcross Flow Rad Core
again at the Bottom of that Item's Page there is a List of Related Parts for it

When you find the Right Shroud and the Right Fan with or without a Clutch
you will then need the Right Length of Fan Spacer // there are various ones listed on the First above Site
this is so you can Place the Fan Blades 1/2 IN and 1/2 OUT of the Shroud Opening
to ensure the Proper Air Flow Pulled into the Engine Compartment by the Fan

Measure the Space you have from the Front of the Engine , to where you will attach the Fan/Spacer to /
the Water Pump / to the Rad Core, this will help you determine the Fan Spacer you will need
also you bo not want the Face of the Clutch to close to the Rad Core /
usually 1" to 1.5" so it can sense the Rad Core Temp
then Measure the Thickness of all the Parts that need to be attached in between
eg. Clutch/Fan/ the Fan Spacer needed
 
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Another Note
Some of the Shroud Openings are Offset to One Side
You want your Engine/Water Pump Snout to be in the Middle of the Shroud Opening
 

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I have a 71 ElCamino with a 400 the shroud I'm using is a SB shroud that fits the large SB radiator.It's a two piece shroud with two different part numbers Top and Bottom.I'll go out and get the part # later and post it for you.I tried using the BBC shroud and the fan hit that's why I switched to this setup.
I believe the Repro houses list this as a 71-75 part. I looked it up on the "ground Up" web site and this is the same one that I have on my ElCo.

Seeing that reminded me of it's part number its 3986905
 

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Our 70 conv was originally a 307/3sp with factory air cond and a ONE row radiator with the smaller 307 fan shroud.
When I built the SB400, I took the stock radiator to my buddy with a radiator shop and had him install a 4 row core to the original radiator upper and lower tanks. I use a stock 7-blade clutch fan and the stock smaller 307 fan shroud.
ZERO heating issues.
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Timing has everything to do with engine heat. Too little, too hot. Reasonable initial, along with the correct vacuum advance degrees, on full manifold vacuum to supplement idle degrees is the right way to do it. The right total idle degrees for a 400 would be 20 to 22, conservative initial, low vacuum degrees added, works.

As far as the cooling system, you have the guidelines in DZ Auto's post above, good Air Conditioning fan clutch, stock fan with a lot of blades, correct shroud, stock pulleys (NO "under drive" pulley setups), good Robertshaw or Mr. Gasket Pressure Balanced 180 degree thermostat (cast iron heads, block), and 50/50 mix of good anti-freeze and tap water (NO demineralized/distilled water, that stuff eats minerals, like aluminum, cast iron, other metals)
 

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I have a 71 ElCamino with a 400 the shroud I'm using is a SB shroud that fits the large SB radiator.It's a two piece shroud with two different part numbers Top and Bottom.I'll go out and get the part # later and post it for you.I tried using the BBC shroud and the fan hit that's why I switched to this setup.
I believe the Repro houses list this as a 71-75 part. I looked it up on the "ground Up" web site and this is the same one that I have on my ElCo.

Seeing that reminded me of it's part number its 3986905
The Problem with that Shroud is - it does not cover All of the Rad Core !!
 

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Discussion Starter · #18 ·
I have a 71 ElCamino with a 400 the shroud I'm using is a SB shroud that fits the large SB radiator.It's a two piece shroud with two different part numbers Top and Bottom.I'll go out and get the part # later and post it for you.I tried using the BBC shroud and the fan hit that's why I switched to this setup.
I believe the Repro houses list this as a 71-75 part. I looked it up on the "ground Up" web site and this is the same one that I have on my ElCo.

Seeing that reminded me of it's part number its 3986905
Is the radiator support on the 71 Camino same distance as a 69 chevelle ?
 

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Discussion Starter · #19 ·
Our 70 conv was originally a 307/3sp with factory air cond and a ONE row radiator with the smaller 307 fan shroud.
When I built the SB400, I took the stock radiator to my buddy with a radiator shop and had him install a 4 row core to the original radiator upper and lower tanks. I use a stock 7-blade clutch fan and the stock smaller 307 fan shroud.
ZERO heating
Our 70 conv was originally a 307/3sp with factory air cond and a ONE row radiator with the smaller 307 fan shroud.
When I built the SB400, I took the stock radiator to my buddy with a radiator shop and had him install a 4 row core to the original radiator upper and lower tanks. I use a stock 7-blade clutch fan and the stock smaller 307 fan shroud.
ZERO heating issues.
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so you have the wider radiator 32” end to end and the smaller shroud from the smaller radiator? So it most likely shroud doesn’t cover entire core any pictures?


View attachment 715410


View attachment 715411


View attachment 715412
So you
 

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Discussion Starter · #20 ·
My setup and yours if the same should work with no issues. The 71 and 72 is larger as is the fan, I believe its 19 inches versing our 17.5 inch. Opening up the core should help.
So did you go with the 71/72 shroud and larger fan ? My new radiator is 32” end to end I’ll open up the of the support with the stamped out area. I measured the distance of existing fan blades to the core it has 4-1/2” on the old smaller radiator
 
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