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Discussion Starter · #1 ·
Hey guys,

My 66 has a built 289 with a 3 row aluminum radiator. I'm thinking I wanna get a 17" flex-a-lite flex fan and I'm wondering what shroud you guys with this fan run??

I was looking at the scott-drake 3.5" wide one but not sure if the 17" fan will fit in it.

any suggestions would be great!!

Thanks
 

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Got mine at NPD, for a 68 w ac 289. Fits and works great on my aftermarket 3 row alum rad
 

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Remember that a proper fit is at least one inch from the core, one inch from the sides bottom and top and a bare minimum of 1/2 in backside clearance around the pulleys and belts. Flex fans are also crazy loud too.
 

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20 or 24" rad and what size fan is ur old one
 

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Discussion Starter · #5 ·
Its a 20" champion aluminum rad and the stock fan was a 5 blade steel one... I bought a 16 inch electric fan but its not cooling enough

so an inch or less from the core, an inch or less from the sides of what? the rad or the shroud? and 1/2" spacing from the pulleys,etc.
 

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at least an inch from the core (no less), at least an inch from the sides of the shroud (no less) and no less than 1/2" from any belt or pulley on the back side of the fan.

Rule of thumb: in front of the fan clearance (and sides) greater than or equal to 1". behind th fan is no less than 1/2". Remember though that u dont want the fan too far away from the core or from the sides of the shroud. this will inhibit the fan from pulling the air through the the rad from the front of the car like u want rather than exchanging warm eng comp air.
 

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Destroy ur rad when the engine torques, cutting ur tubes and sending coolant spraying wildly everwhere. Very very bad
 

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What size fan spacer are you using, on my 65 i have a champion 3 row aluminum and had to get a spacer 1/2'' shorter, i got the polished aluminum 2 1/4 spacer scott drake makes and i am using a 17 inch flex a lite fan. I used the stock style cheap metal shroud for 65-66 the thicker one would probably be better as some of the fan is outside the shroud.
 

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my spacer is a 1.75. you want the blades half in and half out of the shroud for it to work (not all the way in though)
 

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Discussion Starter · #11 ·
between my radiator and water pump pulley i have 3 3/8". So flex-a-lite's website says the fan is 2 1/4" inches wide so that only leaves me with 1 1/8" of space.. so maybe I have to cut my 1" spacer in half?
 

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Autozone has spacer kits for $9 that iclude new hardware (which u will need anyways). The 2.25 is the pitch on the blade, not how far it sticks out. Meaning that if u lay the fan flat, the flex blades are then flexed back 2.25" and flatten as the rpm goes up. I take u dont have the fan yet but u will be fine. But more than likely u will need a bigger spacer. Hope that makes sense, u r more than welcome to pm me for my number if needed. I just had surgery on my shoulder so it is hard to type
 

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Having used that flex fan, and worked on cars with others like it, I have a very definite opinion of flex fans:

They suck.

They pump air hard and fast, alright, summer, winter, rain or shine. High engine rpm they sound like a Piper Cub trying to take off.

You want even better cooling, with improved mileage and power, and no airplane sounds from under the hood, use a thermal clutch fan.

Works with the stock steel shroud, and moves a LOT of air, but only when you need it.
 

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Running a 17" 7 blade flex fan with a cast FoMoCo 2 15/16 spacer and an original narrow OEM shroud. The forward edge of the blades are 1 3/16 away from the rear face of the 3 core copper radiator. This is about the minimum that you can get the bolts into the water pump pulley and have room to tighten them without pulling the radiator.

The blades are 1/2 in the shroud and 1/2 out and there is about 1 3/16 clearance between the tip of the blades and the shroud.

This is all on a '65 2v 289 with a 180° stat. It runs perfectly, cool out or hot. I also do not find the noise of the flex fan to be excessive.

I do not live or drive the mustang in extreme cold or even in our coldest months, but warm up time is otherwise pretty quick, even in 50° weather, once you get up and down the highway.
 

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Discussion Starter · #15 ·
Thanks erik I'll pm you if I need some more help

The fan should be here by wednesday and I'll post what I find out. I have the stock fan spacer, a 2.25" spacer, and a 1" spacer so hopefully one of them will give me the correct clearance.

So even though the flex fan says 2.25" that would be how close it is to the radiator? I'll just have to make sure the blades clear the pulleys/belts.

I think I'll keep the 3.5" shroud though I like how it looks.. and I'm not sure what I did with the stock spacer after I tore down the engine & engine bay :laugh:
 

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the 2.25 is how far the blades are curved back from the flat plane of the mounting surface. Where the fan mounts is flat and the blades go back 2.25" from there. As you increase RPM, the blades come closer to the same plane as the mounting surface, thus giving less drag etc... You'll will be fine, let me know how it goes
 
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