1966 Bel Air Fan Shroud Question - Impala Tech
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post #1 of 8 (permalink) Old 06-07-2016, 12:12 PM Thread Starter
 
 
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1966 Bel Air Fan Shroud Question

Gents-

Here are pics of my 1966 Bel Air radiator....car has a big block, but did not come with one originally.....have no idea which radiator this is, but it is different from my original 396 equipped Impala. If you look carefully, you can see a bracket (SPACER?) that extends from the radiatior on both sides towards the engine....I just want to get the right shroud. Motor not running hot, but a shroud does serious work, and I want to get one!

Thanks in advance for the help!

Brad
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post #2 of 8 (permalink) Old 06-07-2016, 12:14 PM Thread Starter
 
 
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Shroud question: cont.

one more pic.....thanks again.
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post #3 of 8 (permalink) Old 06-07-2016, 12:29 PM
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You have a top down radiator (the factory went to cross flows so they could lower the hood line in 1967) so you will need to stay with that style. Top downs have a bolt on fan shroud with the thickness of the spacer reflecting the length of the motor. A SBC was the shortest engine so it had the thickest spacer. Then the Goldilocks spacer would be for a BBC that was two inches longer than a SBC but not as long as the extra two cylinders on a six cylinder engine. The six cylinder got a fan shroud only if the car had A/C.

You want the fan blades (hopefully you have at least a five bladed fan but you will cool better with a newer seven bladed BBC fan) half in and half out of the shroud as the shroud has to keep air from being flung off the ends of the blades. A shroud, the number of blades on your mechanical fan, thermostat , radiator width (core size in area) and the number of radiator cores if a copper brass radiator all contribute to how well your car can shed excess heat. You want the block to be as cold as you can get to maximize your Carnot efficiency.

Big Dave
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post #4 of 8 (permalink) Old 06-07-2016, 12:36 PM Thread Starter
 
 
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Quote:
Originally Posted by Big Dave View Post
You have a top down radiator (the factory went to cross flows so they could lower the hood line in 1967) so you will need to stay with that style. Top downs have a bolt on fan shroud with the thickness of the spacer reflecting the length of the motor. A SBC was the shortest engine so it had the thickest spacer. Then the Goldilocks spacer would be for a BBC that was two inches longer than a SBC but not as long as the extra two cylinders on a six cylinder engine. The six cylinder got a fan shroud only if the car had A/C.

You want the fan blades (hopefully you have at least a five bladed fan but you will cool better with a newer seven bladed BBC fan) half in and half out of the shroud as the shroud has to keep air from being flung off the ends of the blades. A shroud, the number of blades on your mechanical fan, thermostat , radiator width (core size in area) and the number of radiator cores if a copper brass radiator all contribute to how well your car can shed excess heat. You want the block to be as cold as you can get to maximize your Carnot efficiency.

Big Dave
Big Dave- (and others!)

thanks so much...For My 1966 Impala 396, the shroud from Classic Industries bolted up to the original radiator.....there was no bracket or shroud, and it cools perfectly...But given this radiator with a spacer, do you know who sells the correct shroud I need? i.e. Hubbards, Classic etc?

thanks for the tutorial!

Brad
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post #5 of 8 (permalink) Old 06-07-2016, 01:10 PM
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Shroud is made of charcoal grey molded fiberglass and the spacer that the shroud bolts to is a steel fabrication of varying thicknesses. Which do you need or both? Are you asking about the originality of your radiator (should have a Harrison tag with a set of numbers punched out that identifies it, soldered to the tank, if it is the original radiator to the car)?

Big Dave
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post #6 of 8 (permalink) Old 06-07-2016, 02:33 PM Thread Starter
 
 
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Shroud for my 1966 Bel Air

Quote:
Originally Posted by Big Dave View Post
Shroud is made of charcoal grey molded fiberglass and the spacer that the shroud bolts to is a steel fabrication of varying thicknesses. Which do you need or both? Are you asking about the originality of your radiator (should have a Harrison tag with a set of numbers punched out that identifies it, soldered to the tank, if it is the original radiator to the car)?

Big Dave
Dave-

I need the shroud only. I can be more clear and less confusing now. Car is a modified 1966 Bel Air...not an original Big block car, and probably not the original radiator at this point to be sure...But not an aluminum etc, close to correct style, probably someone's reproduction, but who knows after that. NOT marked Harrison as is my Impala's. My impala's radiator has an integral bracket / spacer that positions the shroud very close to the back of the radiator. this Bel Air's radiator's integral bracket extends farther towards the motor, which is good, as the fan blade is bit farther away from the radiator than it is on the Impala. The impala's fan is approximatley 1 1/4" from the radiator fins, vs. 2"" on the Belair. Which is why I guess the integral bracket / spacer on the Bel Air's radiator extends farther back towards the fan. Both have five blade fans, of approximately 17" in diameter...both with fan clutch assemblies. Bel Air is a 454 and Impala a 396, which I think are the same length. I do not need any kind of a bracket, just want to get the right shroud to attach what I erroneously called a bracket, but which is actually attached, or part of, the radiator on both sides. The impala shroud'se mounting points were approximately 12" on centers. The Belair's holes on the side of the mounting points for the radiator are not 12". Unfortunately the photos are very low resolution, as that is all that is allowed....i see two styles of shrouds: classic industries has this, which I call an "early" shroud. 1966 Impala Parts | C1109 | 1965-66 Impala / Full Size With Big Block Fiberglass Fan Shroud | Classic Industries

Here is a second of this type: it mentions holes need to be drilled, and that it is for a/c equipped cars...mine is not an a/c car of course:

https://www.yearone.com/Product/1958...85#prettyPhoto



and this is the one is the one I bought from impala bobs that bolted directly to my Impala's Harrison marked radiator:

1965-1966 Impala Fiberglass Fan Shroud 396/427 Big Block

But, again, my Impala's radiator had its' integral shroud mounting extending from the radiator towards the fan in a much less pronounced fashion than does the Bel Air's NON Harrison marked radiator....probably an inch or so less, so it was hardly noticeable... The shroud went straight to the fan side of the radiator. this photo is of my 66 impala set up.

I just need to know which shroud! I think I can probably modify the flatter style shroud's mounting holes I used on the Impala for this application, but I did want to ask! Better to measure twice and cut once!

many thanks!

Brad
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post #7 of 8 (permalink) Old 06-07-2016, 02:40 PM Thread Starter
 
 
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Wrong Photo in Previous post

Quote:
Originally Posted by griffbl View Post
Dave-

I need the shroud only. I can be more clear and less confusing now. Car is a modified 1966 Bel Air...not an original Big block car, and probably not the original radiator at this point to be sure...But not an aluminum etc, close to correct style, probably someone's reproduction, but who knows after that. NOT marked Harrison as is my Impala's. My impala's radiator has an integral bracket / spacer that positions the shroud very close to the back of the radiator. this Bel Air's radiator's integral bracket extends farther towards the motor, which is good, as the fan blade is bit farther away from the radiator than it is on the Impala. The impala's fan is approximatley 1 1/4" from the radiator fins, vs. 2"" on the Belair. Which is why I guess the integral bracket / spacer on the Bel Air's radiator extends farther back towards the fan. Both have five blade fans, of approximately 17" in diameter...both with fan clutch assemblies. Bel Air is a 454 and Impala a 396, which I think are the same length. I do not need any kind of a bracket, just want to get the right shroud to attach what I erroneously called a bracket, but which is actually attached, or part of, the radiator on both sides. The impala shroud'se mounting points were approximately 12" on centers. The Belair's holes on the side of the mounting points for the radiator are not 12". Unfortunately the photos are very low resolution, as that is all that is allowed....i see two styles of shrouds: classic industries has this, which I call an "early" shroud. 1966 Impala Parts | C1109 | 1965-66 Impala / Full Size With Big Block Fiberglass Fan Shroud | Classic Industries

Here is a second of this type: it mentions holes need to be drilled, and that it is for a/c equipped cars...mine is not an a/c car of course:

https://www.yearone.com/Product/1958...85#prettyPhoto



and this is the one is the one I bought from impala bobs that bolted directly to my Impala's Harrison marked radiator:

1965-1966 Impala Fiberglass Fan Shroud 396/427 Big Block

But, again, my Impala's radiator had its' integral shroud mounting extending from the radiator towards the fan in a much less pronounced fashion than does the Bel Air's NON Harrison marked radiator....probably an inch or so less, so it was hardly noticeable... The shroud went straight to the fan side of the radiator. this photo is of my 66 impala set up.

I just need to know which shroud! I think I can probably modify the flatter style shroud's mounting holes I used on the Impala for this application, but I did want to ask! Better to measure twice and cut once!

many thanks!

Brad
here is a photo of the Impala's shroud...this one came from Impala Bob's...

I do not see how to edit your own post on this forum...sorry!
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post #8 of 8 (permalink) Old 06-07-2016, 07:37 PM
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You can not edit your own posts after a few minutes of inactivity. That is how I got sucked into being a moderator here as only moderators can edit a post after it times out, and I hated reading old posts were I used poor grammar or mistyped something because my typing finger gets thicker and harder to control as I get tired. I wanted to edit my old post so badly that I volunteered as a mod just to be able top do that.

I don't know what to tell you with a mixture of aftermarket parts. I believe you are on the right path, and you will have to modify something to get the parts all to fit together. I went the aluminum radiator route (a Griffin aluminum stamped tank radiator looks stock painted black) with auxiliary coolers for oil and tranny to get the heat out. With a dyno proven minimum of 750 horse and it ran at 185 degrees all day long in Florida. If I hit the bottle the temp would climb as I could nearly double my rear wheel horsepower; such that I owned the only low nine second Taxi cab in town (a 1985 Impala 4 dr sdn)

You are correct, in that there are precious few differences externally between a 396 and a 496 (a 454 with a quarter inch stroker crank). I grew up playing only with big blocks so I am familiar with them intimately. There are not many others at a car show who can tell them apart, which is why I chide people for installing a 396 in anything other than a numbers matching museum exhibit. In terms of power per pound a 350 SBC will beat it and one knows if your 375 horse 396 decaled big block is a 454, a 555, or a 632: as they all look alike, and weigh the same, so why not go large?

Having run many 500 plus cubic inch big blocks with a 402 decal (why cars were all made after the 396 was discontinued) I have learned that as power goes up so does the need to cool them down as roughly one third of the heat of combustion is shed to the coolant and has to be removed by the cooling system. This is just plane physics and has to do with the laws of thermodynamics. More power, more heat, plane and simple.

Big Dave
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