Would someone help identify this fan blade?

[Larry Rosamond]

I have a blade in my possession which supposedly came from a 66 big block. However, I have my doubts that this is correct. It is a 5 blade fan with a 17" (or possibly 17 1/8) diameter. The blades are 4" x 5 5/8" (5.68) attached with 5 flat rivits. The blade pitch is 29 degrees. There is an H stamped on the hub face and a W stamped on one of the arms on the backside. All of the info matches Noland Adams description of a blade for a small block, no a/c car. However, Noland does not provide the bolt circle diameter for clutch attachment. The bolt circle diameter on this blade is 3".

I have heard that the bolt circle is different for small blocks vs big blocks. Does someone know the bolt circle diameter on small block 63-67's and is it in fact different than the 3" diameter of the big blocks?

As always thanks and regards. LR

[Dale Pearman]

Re: Would someone help identify this fan blade?

Sounds like a Chevrolet passenger car with air or a 396 cu in Corvette without air.
Are you SURE of the 17 1/8 measurment? 17 1/8 is a 1961-62 Corvette fan BUT an "H" was never present. All the "H" fans I've ever tried to use on 61-62s are too big and interfere with the shroud. They measure 17 1/2 and up. Is there a "FRONT" stamped on the blade near the hub?

Dale.

[Larry Rosamond]

Answers....

No, I am not positive on the 17 1/8 measurement: it's more likely 17", it was difficult for me to get an accurate diameter dimension. Also, FRONT is not stamped on the blade. I think it is highly unlikely that this blade is from a 396 car as Noland states that the blade angle would be 34.5 degrees, not the 29 that this blade measures.

Thanks and regards, Larry

[Joe L.]

Re: Would someone help identify this fan blade?

Larry-----

The fan clutch mounting bolt circle diameter for Corvette fan blades was EXACTLY the same for small blocks and big blocks during the 65-70 period. That bolt circle diameter is, indeed, 3".

Beginning in 1971, for BOTH small blocks and big blocks, the fan clutch mounting bolt circle diameter was changed to 3-1/4".

The water pump/fan clutch/fan blade assembly is only interchangeable as a complete unit from pre-71 to 71+ and vice-versa. Even then, if the systems are interchanged, other components also have to be changed (e.g. crank and alternator pullies).

[Ray C.]

Re: Would someone help identify this fan blade?

Hi! Dale

If the fan did have the word FRONT, what would this represent.

Thanks! Ray

[Dale Pearman]

Re: Would someone help identify this fan blade?

It would represent something I would NOT buy for a C1.

Dale.

[Peter L.]

Re: Would someone help identify this fan blade?

Larry - From your description, I'd say you have a P/N 3770529 fan blade assembly which is '66-67 Corvette 327 w/o A/C (might fit others but I'm sure about the '66 & '67 applications). The "H" on the front of the center hub of the support and "W" on the back of one of the supports and 17-1/8" diameter fits; although they all might not have the "W" on the back of one of the supports. A little more detail is the supports for the blades are elongated triangles, the five rivet heads are flat and form a T (2 rivets across the top and 3 down the leg, there are 4 holes for the clutch bolts (opposite ones are 3" apart) and the center hole in the support is 2-3/8" in dia. Also, where the rivets attanch to the blade the surface is flat not depressed as on some fans. If this all fits, you're right it's for a sb. Pete

[Larry Rosamond]

The 3" bolt circle cinches it...

This is a small block,no a/c blade. Thanks to all who assisted. Regards, Larry