hi i got a flex a lite fan 10,ooo rpm also got the bolts and spacers , can you tll me do i need washers and lock washers with this fan??thanks storm

Yes. Just to ask, why are you using a flex fan? You will run cooler with a clutch fan.

my engine guy said the opposite ill run cooler with a flex fan . anyone???

He is dead wrong. The 454 that we had would overheat quickly in traffic with a flex fan and proper shroud. Switching to a clutch fan cured it 100%. Less drag on the engine when its not needed also.

Dad's 72 heated up with a flexfan, didn't see any gain over a stock style fan either.

Get a clutch fan or run electric fans.

i think i will hold off on the electric fan for now i just got the flex fan today so now i got to decide about that and i got to tackle my radiator thats the next step. i have a clutch fan from my 307 and an extra one from a 350 will any of these still be worth putting on?

Slow down guys... He said "flex a lite" and they make many different fans... I have one of these... http://www.flex-a-lite.com/auto/html/clutch-fans.html and it is a great product.

Storm - An actual flex fan is designed more for drag racing than the street. At low RPM it scoops lots of air but as the RPMs increase the blades go flat and don't pull much air through teh rad core. Also the flattened out blades block the speed induced flow through the core. Another trate of the common flex fan is the stainless blades are rivited to the frame and the flexing puts stress on the rivits which can lead to a blade flinging itself around under your hood. There are some newer designs that some of the well versed cooling gurus seem to recomend. I know one is made by derail (sp?)

I know guys running flex fans without the problems I've mentioned but I've never heard anyone complain about a fixed of clutch fan...

i have the 1300 series . about 2 or 3 weeks ago i posted the same question and the guy raved about the flex fans now its on the clutch side everone say go with the clutch now another choice to make.

In the Heating and Cooling forum, HOTRODSRJ, Steve Jack recommends the DeRale fans. You might email Steve and ask him, he always gives good advice on this site.

I use the Derale Heavy Duty Chrome fan (the HoTrodSRJ one) on a 350 small block , and think its SUPER. Ive never had a prob getting hot. I noticed a difference over the stock fixed fan. Clutch fans are OK, but I had bad luck with a clutch on one going south, so that was enough for me. I really doubt that the clutch fan is really that much better...plus, the hub/blade attachments on teh Derale look to be practically bullet proof, unlike the cheapy flex fans. Actually, I think Pontiac used to put flex fans on GTOs in the early '70s, and teh Derale kinda looks like an updated version of that.

i was runnning a stock 7 blade fan with a high quality clutch unit($65). well it let go and took out a new radiator and shroud. others have a better experience. just sharing mine. mike

I was running a Flex a Lite flex fan on my 70 for about 2 months until it overheated on me. I swapped over to a heavy duty 7 blade clutch fan from a Cadillac and have not had any problems since.

I couldn't stand the noise it made. Sounded like a turbo winding up.
At 6200 rpm all I could hear was the fan howeling.

I tried to fit in a clutch fan but with the Zoops pulleys and Griffin radiator I couldn't fit one so flex or a standard pitch fixed were my only options on my 66.