I want to put on this new flex fan I bought. Its a 16 7/8 inch fan, picked it up at Orileys because my fan got mangled. I knocked the old stock fan straight (kind of) but it is a little off and being that its attached to my waterpump I am afraid that it might induce a little extra wear onto the bearings of the pump at high RPM and cause some problems.

Anyway, the box that the fan came in says that it should not be used for engines larger than 250 CID or 4.1 liters... Why?

Should I not use this flex fan then? It seems like it would work just fine. I picked up a used radiator to last me for the next few months until I get back to california and can put in an aluminum radiator.

So is it ok to put this flexfan on my 351w

 

I don't recommend them. For one, I've seen what happens when they come apart. It's not pretty. For another, they're noisy.

I went from a 6 blade steel fan to a flex fan, then quickly ditched that in favor of a clutch fan setup. I'm very happy with the clutch fan. It's a little more initially than the flex fan, but it frees up some power (noticeably) and is much, much quieter. It cools just fine.

 

+1 to the clutched fan. I went with an oem fan for a '66 Mustang with air and found the clutch at Pep boys. A Hayden but can't remember (nor kept the docs) the number.

 

My guess is that the fan was designed to move enough air to cool 250 cid. In my head, I cant see where durability would be an issue because in my mind, durability, as it relates to design limits would be more a function of the RPM that the fan operates at than the size of the engine.

IMO, if you were to use this fan it would be ok so long as it cools your engine.

 

I would not use it and like said before, install a gool ole clutch fan.

 

I agree, I ditched a flex fan years ago for a thermal clutch fan. Works very well, only pumps air when hot, freewheels quietly the rest of the time, saving me gas and improving power.

I have a brass 3-row, shroud, 17" fan, thermal clutch, and AC, driven by a 289 High Performance engine bored .030" over. This is not my engine, but my setup is identical-

 

The flex fans suck lots of power,are noisy and can be dangerous as some of them tend to fail at high rpms...The upside is they do move lots of air.

 

felxfan here, but it's going to be changed wheneve I am bored. was one of those projects that was moved back ... make sure you
- get clutch fan setup
- have the correct distance to rad
- use a shroud and make sure fan is half in/half out of shroud.

Kalli

 

I think Ill just put it on for now and if I have to get another fan later, then Ill just be out $35. Im afraid that the stock 4 blade on it right now being that I hammered it strait(ish) is going to kill my water pump.

Thanks guys.

 

Trying to keep on budget, I would do the same.

The old fan wouldn't worry me about the pump so much as it would about being bent, straightened, weakened, and then flying apart. For me it would depend on how much it got bent, but still, it is approaching fifty years old anyway....