5 blade fan

[Keith L.]

I need a fan for my SB non AC 72. Is a 69 the same? If not would it be ok for a driver? What years are the same as 72?

[Joe L.]

Re: 5 blade fan

I need a fan for my SB non AC 72. Is a 69 the same? If not would it be ok for a driver? What years are the same as 72?

Keith-----


1969 fans are NOT the same as those used for 1972 and will not interchange. You need a GM #3991420 which was GM-discontinued quite a few years ago. I'm not sure if it's reproduced, or not.

You can use a 7 blade GM #342715 which will work perfectly and might even provide a little better cooling. It's still available from GM for about 140 bucks, GM list.

[Keith L.]

Re: 5 blade fan

Thanks Joe. I know about the clutch flange being different. This one has the universal mounting slots. So are you saying it still won't work? Is it a different size?

[Joe L.]

Re: 5 blade fan

Thanks Joe. I know about the clutch flange being different. This one has the universal mounting slots. So are you saying it still won't work? Is it a different size?

Keith-----


The slotted flange only serves to accommodate the 2 different WATER PUMP HUB bolt patterns. Although there may be some, I have never seen a fan clutch designed to accommodate the 2 different fan blade-to-clutch mounting patterns. The 1960-70 fan blade assemblies used with fan clutches used a 3" bolt circle; the 1971+ used a 3-1/4" bolt circle. So, if you have a 1971+ fan clutch, you cannot mount a 1969 fan.

[Alan S.]

Re: 5 blade fan

Hi Keith,
Here are a couple of pictures of the fan from my 71 s/b no a/c car. Theres no part number stamp, just the H and W.
Perhaps Joe can tell us if this fan would be correct for your 72 also.
Regards,
Alan

[David L.]

Re: 5 blade fan

Keith,
The 3991420 fan was used on 1971-1979 Corvettes (exc. AC) so finding a good used one should not be that difficult. As shown by the pictures by Alan the 5-blade fan measures 17 1/2" in diameter (8 3/4" from the center of the hub hole to the tip of any blade). The bolt circle is 3 1/4" and the hub hole is 2 5/8" in diameter. The fan is made by Hayes-Albion ("H" stamping) and has 5 rivets/blade with the blade connectors shaped like arrowheads. I do not know the significance of the "W" stamping although it appears on many Hayes-Albion fans on the back side. I may have a 3991420 fan in my "collection" (of about 40 or more fans) as I believe I still have the original fan-clutch (made by Schwitzer) dated "F0774" (June 7, 1974). If I still have the fan I will let you know.
Dave