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Discussion Starter · #1 ·
I have this 5 bladed 18 inch fan with rounded blades and 5 rounded rivets on each blade. Could it possibly be correct for a 1966 325HP 396 with air conditioning? My El Camino built at KAN in December of 1965 would be the recipient. I know the clutch is not correct.


 

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does it have a "W" stamped into it? also it all has to do with the configuration of the rivets
 

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Discussion Starter · #3 ·
Hi Keith,
No W, just FRONT and H. Here are some more photos.


 

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well your fan was made by Hayes-Albion and that style rivet was used in 65-66.
 

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Discussion Starter · #7 ·
Thanks Keith. I went out to the shop to verify that there wasn't a W. While there I measured the pitch. I noticed on the Long Island Corvette site that the listed fans appear to be either 25 degrees pitch or 34.5 pitch. The one in my photos measures 30 degrees. Is 30 degrees unusual?
 

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Thanks Keith. I went out to the shop to verify that there wasn't a W. While there I measured the pitch. I noticed on the Long Island Corvette site that the listed fans appear to be either 25 degrees pitch or 34.5 pitch. The one in my photos measures 30 degrees. Is 30 degrees unusual?
I could not tell you yes or no. there was quite a lot of variations used on many different cars and since there was no part number stamped on them until 68 it can be hard to positively id it. my parts book doesnt list pitch as a way to measure them.
 

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Discussion Starter · #9 ·
I was researching the 3789562 fan, trying to learn as much as I can about them, hoping that the fan I have is one of them. I suspect it is, just don't know if it is too early for my El Camino.

I solved a mystery while looking through my parts price and history books. Found out that the 3789562 fan was discontinued on 5/72 and replaced with part number 3931002. 3931002 is a 7 blade 18 in. fan with aluminium blades.

When I bought my EC in 1983 it had one of these 3931002 fans with a date code of C74. So now I know that this fan was a service replacement. But I don't know why it was replaced. My EC still has its original radiator and waterpump but the clutch was replaced.

I measured the pitch of this service replacement fan and it is 30 degrees, the same as the fan I am posting about. So could this be an indication that 3789562 fans were 30 degrees?
 

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AZCamino;9515274 I measured the pitch of this service replacement fan and it is 30 degrees said:
it very well could
 

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Discussion Starter · #11 ·
This is how I measured the pitch. Is this the correct way to do it?
 

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That blade is correct for all early 66's with clutch fan. Later in the year they went to blades with flat rivets, but I am not sure when the change occurred. All L78's all used the flat rivet blades (first with 4 rivets and then later with 5).

The clutch is a Schweitzer (sp?), and could be correct, as both Eaton and Schweitzer supplied the clutches (if I remember correctly the AIM has both part numbers listed). Some of the Schweitzers have a date code stamped on the edge of the part that bolts to the water pump. You should check for that.
 

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Discussion Starter · #13 ·
Thanks for the reply, Jeff.

About the fan clutch, this clutch was on my EC when I bought it in 1983 and had the service replacement 7-blade fan on it. I always thought original clutches had bolt holes, rather than the slotted mounts, so I never thought it could be an original. Here are some photos of it including a photo of the stamped date code (?). I am not sure how to interpret this, but my guess would be 12 month of 1974. So it wouldn't be an original, but possibly a service replacement like the fan blade. Did originals have slots or bolt holes where they mounted on the pump?


 

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Sorry about that, I didn't even notice the slotted holes in your first pics, I was looking at the face and didn't pay enough attention to the mount. You are correct, the slotted holes came later so as to allow one clutch to fit either size water pump mount (large or small bolt pattern).
 
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