[davehurst]

I got a 1966 Chevelle, run a 454 with long water pump. I have 2-3/4" appox. clearance from fan to radiator.
other stats, Alum radiator, shroud, 160 thermostat.
I currently run a Flex Fan and a 14" electric (on front) fan. During the Nuclear Summers here in Deep south I can keep it at 200 deg. in traffic.
I am happy with that. I can keep it at 180-190 driving.
But it sounds like a damn Bus taking off, I know it's the flex fan raising hell, So with out spending hundreds of dollars, I thought a OEM stock 5 or 7 not sure on blades might be quitter and keep it cool also.
I don't have enough room for a clutch fan or good high CFM electric fans.

My question is 5 or 7 blade which is best?

and will they cool better or just as good as the Flex?

 

[vortec710]

FWIW...On my 70 Chevelle that was a factory A/C car it used a 7 blade clutch fan, the non-A/C cars a 5 blade fan was common, you may wish to consider a 7 blade fan as it pushes more air, the Flex fans tend to be noisy

 

[Bronze68]

In my experience, flex fans are worthless pieces of bling under the hood that don't do much for cooling, and I have seen many with cracks. Personally, I've always had great cooling with the standard GM 7-blade clutch fan.

 

[dyno jonn]

In my experience, flex fans are worthless pieces of bling under the hood that don't do much for cooling, and I have seen many with cracks. Personally, I've always had great cooling the standard GM 7-blade clutch fan.

Flex fans ain't worth the power to blow them to hell. They're dangerous, blades can crack and damage cars or kill people. Clutch fan or electric fan, with clutch fan being first choice for price and cooling.

 

[Kirk's67SS]

Putting the Flex Fan noise aside the worst / main reason for High Temps is the 14" Efan infront of the Rad
as it blocks/restricts/impedes Air Flow that is trying to go thru the Rad that would Cool the Coolant down
Here is what I have on my 67 454/468 ci BBC with 500+ HP

• Stock Sized Down Flow Alum Rad with 2 Rows of 1.25" Wide Tubes / Core Thickness = 2.75"
• SPAL Dual 11" Efan/Shroud with 2,720 cfm 4.25" Deep at the Motors and in the Middle less 2"

SPAL 30102052: Dual 11" High-Performance Fan 12V | JEGS

• Weiand Short Water Pump Wei& 9212: Aluminum Water Pump BBC | JEGS
• 160* Thermostat
• A Trans Cooler Located Down Low & away from infront of the Rad

On the Hwy with one or no Efan she runs about 170*
on the City Stop and Go streets with both Efans on she runs about 180* to 190*
and at the Track after Back to Back 1/4 Mile Runs she runs 180* to 190*
each start of the Run down the Track she is usually at 165*/170*

 

[keithb]

a stock short water pump, stock fan shroud, stock five blade clutch fan and the correct timing/ spark map you will be fine