Correct fan clutch for 68 big block

[Steve B.]

A friend had asked me if this fan clutch is correct for a 68 big block. I am not sure if it's correct, I am used to seeing these with a star type patten surrounding the bar on the radiator side. I would love to know for sure. Thanks in advance.http://cgi.ebay.com/ebaymotors/ws/eB...EF:MOTORS:1123

[Steve B.]

Re: Correct fan clutch for 68 big block

Here is a picture of the fan clutch that I know is correct.

[Grant W.]

Re: Correct fan clutch for 68 big block

Hi Steve
The star burst you have is for a Big Block mid year. Could be used for 65 and for sure a 66 and 67, It has the short shaft for Big Block.
The ebay link is correct configuration for a 68 to early 70. Flange measured at 2 3/8ths across.
71 to 75 same style configuration but the flange is larger at 2 5/8ths across.
Most have dates stamped on the edge of the flange.
I have about 10 of the 68 fan clutches. Ask your friend to email me and maybe I have a date for his car.
Thanks, Grant

[Joe L.]

Re: Correct fan clutch for 68 big block

A friend had asked me if this fan clutch is correct for a 68 big block. I am not sure if it's correct, I am used to seeing these with a star type patten surrounding the bar on the radiator side. I would love to know for sure. Thanks in advance.http://cgi.ebay.com/ebaymotors/ws/eB...EF:MOTORS:1123

Steve-----


This style fan clutch was used on some big blocks but not L-88. This style clutch was GM #3937771.

[Jack C.]

Re: Correct fan clutch for 68 big block

I also believe that the 68 and up have the bolts that screw into the fan clutch and not the studs.

[Steve B.]

Re: Correct fan clutch for 68 big block

Steve-----


This style fan clutch was used on some big blocks but not L-88. This style clutch was GM #3937771.

Grant, thank you for the info. I need to know if it's correct for a 68 L88? Joe, was the 68 and 69 L88 fan clutch like the one that I have pictured?

[Wayne M.]

Re: Correct fan clutch for 68 big block

This style fan clutch was used on some big blocks but not L-88. This style clutch was GM #3937771.

Joe -- my P&A30B [rev 10-1-69] shows this # 3937771 as service for '69 w/A.T., H.D. 427, as well as a bunch of other big and small block Corvettes ['68-9 w/H/Per. (427) (2nd design) (exc. 3x2); '68-9 w/Sp. H.Per (427) (2nd design); '68-9 w/C.A.C. (exc. 427 w/4BC); '69 w/H/Per. (350).

[Joe L.]

Re: Correct fan clutch for 68 big block

Grant, thank you for the info. I need to know if it's correct for a 68 L88? Joe, was the 68 and 69 L88 fan clutch like the one that I have pictured?

Steve------


Yes, I believe that the one in your photo is among those used for 68-69 L-88. The one shown is the Schwitzer-manufactured version. The Eaton-manufactured version was also used. The Eaton version is still available today under GM #3916141 although its configuration is not exactly the same as the one originally used.

[Joe L.]

Re: Correct fan clutch for 68 big block

Joe -- my P&A30B [rev 10-1-69] shows this # 3937771 as service for '69 w/A.T., H.D. 427, as well as a bunch of other big and small block Corvettes ['68-9 w/H/Per. (427) (2nd design) (exc. 3x2); '68-9 w/Sp. H.Per (427) (2nd design); '68-9 w/C.A.C. (exc. 427 w/4BC); '69 w/H/Per. (350).

Wayne------


It's very possible that the 3937771 was used on 1969 L-88/ZL-1 with THM-400. There were few enough of those ever built that I don't know I've ever seen one with a known-original fan clutch. Most 1968-69 L-88/ZL-1 used the GM #3916141 for both PRODUCTION and SERVICE.

[Ray K.]

Re: Correct fan clutch for 68 big block

Steve,

My P & A catalog dated 5-1-69 definitely lists the 3916141 clutch unit
as correct number for 68-69 H. D. 427 (L-88 ) applications.

Ray

[Jack H.]

Re: Correct fan clutch for 68 big block

Note Joe said "this style" and not "this clutch"...

The '771 has an almost twin brother that was NOT used on Corvette. In order to tell the difference, you need a sideview picture that tells you the height of the center cooling fins relative to the outer housing lip.

The fins on a real '771 extend high...almost equal to the level of the outer lip. The 'brother' to this clutch has shorter center fins that fall appreciably below the top of the outer ring.

For the HEAFTY price this seller is asking, I'd make SURE it was a real McCoy '771 before I laid down a bid!