[unruhjonny]

I don't think there ever was a factory seven blade flex fan;

As I have come to understand, this is how Pontiac V8 fans were:
- 4 blade fixed
- 5 blade flex
- 7 blade fixed; clutched

It is also worth noting that generally speaking the different fans used different spacers.

The four blade pictured above does have a spacer that I generally associate with the flex fans...

I am very glad that I posted here, because this has been a great discussion so far!

['ol Pinion head]

Originally Posted by unruhjonny

I don't think there ever was a factory seven blade flex fan;

As I have come to understand, this is how Pontiac V8 fans were:
- 4 blade fixed
- 5 blade flex
- 7 blade fixed; clutched

It is also worth noting that generally speaking the different fans used different spacers.

The four blade pictured above does have a spacer that I generally associate with the flex fans...

I am very glad that I posted here, because this has been a great discussion so far!

Disagree, have owned 2 of the factory 7 blade variable pitch, ie, flex fans. The factory 7 blade flex fan is just not something that is commonly run across.

4 blade......................19" diam 2 5/16" pitch #97xxxxx (later replacent is 9798940)

5 blade var pitch.........19" diam 2 5/16" pitch #9791346
(first use '67 models, a few made it onto '70 model GTO's before replaced by 480033)

7 blade var pitch.........19" diam 2 1/2" pitch #9796135 (HDC usage, have only found on big cars)

Not even going to get into all the different 7 blade different diam AC fans, too many styles.

[Formulajones]

Originally Posted by 'ol Pinion head

Disagree, have owned 2 of the factory 7 blade variable pitch, ie, flex fans. The factory 7 blade flex fan is just not something that is commonly run across.

Correct, the 7 blade flex direct drive fans are a factory part with a part number. I believe they were more common in Chevrolet applications. I have about 5 or 6 of them here. I used to by them all the time and upgrade the cars with them for better cooling.....man those things move some serious air.
In the 1980's I used to run across them all the time at swap meets for $20-$30, I'd just snatch them up.
I don't use them as much anymore because they soak up some HP, lol I have one car here that is currently still running one. I switched all my other cars over to 7 blade clutch.
Dad's 69 GTO had the factory 5 blade flex, but he has also switched that car over to a 7 blade clutch.