Factory fan 1966 L79

[David L.]

Re: Factory fan 1966 L79

Same with an original '529' (was off a '64) that I have. Mushroom head rivets, just the 'H' on the front hub; no 'FRONT' stamping, or no 'W' on the backside spider.

Wayne,

I believe the 60-64 Corvette "529" fans have "dome" (or "mushroom") head rivets while the 65-67 Corvette "529" fans have "flat" head rivets.

My original 66 Corvette "529" fan (which I just put on Ebay) has "flat" head rivets and has the "H" and the "W" stampings.

My NOS "529" fan in a 1986 GM box has "flat" head rivets and just the "H" stamping.

Dave

[David L.]

Re: Factory fan 1966 L79

Dave -

My all-original/unrestored '69 Z/28 has its original 7-blade fan, stamped 3947772 and "914087 L68" on each blade, with the squared-off spider (for which I've been offered obscene amounts of money); I've seen other originals with nothing stamped on the blades and the "arrowhead" spider, so there were obviously several suppliers for this fan too.

John,

The 69 Z28 used 5 different fans. "Very early" 69 Z28 models used the 67-68 Z28 5-blade Hayes-Albion 18" fan (GM #3871276, stamped "H" & "FRONT" and "W" on the back) w/steel blades and 4 rivets/blade (1 5/8" pitch) because the 7-blades fans were not available at the start of 1969 production.

"Early" 69 Z28 models used either the 3937779 (914033) 7-alum. blade (2" pitch) Schwitzer "dated" fan or the 3947838 7-alum. blade (2" pitch) Hayes-Albion "non-dated" fan stamped "H", "FRONT", and sometimes "84".

"Late" 69 Z28 models used the 3947772 (914087) 7-alum. blade (2.25" pitch) Schwitzer "dated" fan or the 3956684 7-alum. blade (2.25" pitch) Hayes-Albion "non-dated" fan stamped "H", "FRONT", and "94" (Hayes-Albion part # 159432).

GM # 3937779 and GM # 3947772 both existed in Oct. 1968 as per my 1969 parts catalogs. GM 3937779 was used on the 69 Z28 & 69 Chevrolet 427 while GM 3947772 was used on the 69 Chevrolet 327,350 w/AC.
GM 3937779 was discontined in Jan. 1969 and replaced with GM 3947772.

I have had all of these 5 different fans.

Since both the 3937779 fan and 3947772 fan were available in the Fall of 1968 I am sure both fans were used on all the assembly lines to keep up the supply. I found a 3937779 fan dated L68 on a "early" 1969 Chevrolet 350 w/AC in a junk yard in Ashburnham, MA, back in the 1980's. According to the books it should have been a 3947772 fan. They did what they had to do to keep the production going.

Dave

[Jim S.]

Re: Factory fan blade assembly for 1966 sb w/ C60

Jim - Please check UPC C60, SHEET C2, ITEM 6, p/n 3789562 BLADE ASM - FAN & p/n 3863137 OPT. of the 1966 Corvette Assembly Instructions. Pete

Thanks Pete,

I least I know I am not getting senile ! On my copy of that page ,items 1 thru 7 are blacked out . As are some of the pictures. I assumed it was a Goverment Cover up !!
Can I get that page from you ?

Jim

[Peter L.]

Re: Factory fan 1966 sb w/ C60

Jim - I trust you have the "need to know" and appropriate clearance to read such information.

The information on your copy is way more secret than on mine. Mine is not the greatest copy but is it readable. What I'll do is make a copy of the page from both my 66 AIM and 67 AIM because the 67 AIM is much clearer.

Send me you address.

Pete

[David L.]

Re: Factory fan blade assembly for 1966 sb w/ C60

Thanks Pete,

I least I know I am not getting senile ! On my copy of that page ,items 1 thru 7 are blacked out . As are some of the pictures. I assumed it was a Goverment Cover up !!
Can I get that page from you ?

Jim

Jim,

Maybe these pictures from my 1966 (picture #1 & #3) & 1967 (picture #2 & #4) assembly manuals might help.

Dave

[Jim S.]

Re: Factory fan blade assembly for 1966 sb w/ C60

Jim,

Maybe these pictures from my 1966 (picture #1 & #3) & 1967 (picture #2 & #4) assembly manuals might help.

Dave

Thanks Dave !

It took guts to defy the powers that blacked out my copy !!( I still think it was Uncle Sam). Keep an eye out for those men in black !

Jim

[Jim M.]

Re: Factory fan 1966 L79

I am impressed by the tremendous response to my question per factory fan . Thanks to all. I will look for a 5 blade (GM #3770529) flat rivets "H" on the front for (Hayes-Albion) and a "W" on the back of the arms. Now the second part of the question, what fan clutch do I look for?

[Rick S.]

Re: Factory fan 1966 L79

Jim,
I am going to step to the sidelines on this issue. My fan clutch is a newer replacement and if I remember correctly Joe Lucia recommends a new replacement for safety reasons. I eagerly await others responses.

Rick

P.S. I drive my car extensively including an occasional trip to the drag strip.

[David L.]

Re: Factory fan 1966 L79

I am impressed by the tremendous response to my question per factory fan . Thanks to all. I will look for a 5 blade (GM #3770529) flat rivets "H" on the front for (Hayes-Albion) and a "W" on the back of the arms. Now the second part of the question, what fan clutch do I look for?

Jim,

Here is a couple of pictures of the ORIGINAL fan clutch that I removed from my 1966 Corvette w/327 300 HP engine and 4 speed (Feb. 24, 1966 body build). The bar strip on the front should have "THIS SIDE UP" stamped on it many times. The clutch was made by the Schwitzer company and dated "SC 1 26 66" (Jan. 26, 1966) on the rim of the water pump mounting hub. I just sold this fan clutch and the original 17 1/8" fan (stamped "H" & "W") as well on Ebay on January 14th.

Dave

[Jack H.]

Re: Factory fan 1966 L79

Now the second part of the question, what fan clutch do I look for

Your copy of the AIM will document GM used TWO different fan clutch parts interchangeably. You'll see one PN called out with a second PN below it labeled [OPT].

Your copy of the Judging Guide proves a textual description of the two different assy's, one made by Eaton (coil type) and the other made by Schwitzer (bar type).

Bottom line, there is no 'correct' fan clutch to search for, there are TWO different ones that will judge without deduction...

[David L.]

Re: Factory fan 1966 L79

I would like to point out that Fords also used the Schwitzer type clutch. In addition to the "SC" and date code stamping on the flange Ford Motor Company also had their part number stamped on as well.
Example: "C4 SA-B" where "C4" signifies the first model year the part was used on, not necessarily the year the actual part was made, in this case, 1964. "C5" would be 1965 and "C6" would be 1966. The actual stamped date code (month, day, and year) signifies when the actual part was made. I got this information from my brother who has sold NOS Ford parts for the last 30 or more years.