Removing original flex fan...hp gains?

[Eagle460]

I want to remove the original flex fan on my 77 351M. Does anybody have a ball park number on any horsepower gains?

Thanks

[unrulee]

No such thing as a factory flex fan.

Personaly speaking I've been through a stock non-clutched fan, flex fan, electric Ford Taurus fand and finally (all in this order mind you) a stock style fan with a thermo fan clutch.

I wouldn't be so concerned with the minimal hp gains as I would with the cooling power. Heat is the enemy and can make for some expensive repairs.

My choice? My current set up (mech fan with a clutch). Second would be the Taurus fan (cooled great, only reason that I removed it was that the controller that I used died within 2 weeks of installation and I wanted something that was stone reliable).

[80broncoman]

Originally Posted by unrulee

No such thing as a factory flex fan.
My choice? My current set up (mech fan with a clutch). Second would be the Taurus fan (cooled great, only reason that I removed it was that the controller that I used died within 2 weeks of installation and I wanted something that was stone reliable).

My factory Flex Fan I took off My 79 truck is part number D7UA-8600-AJA.
It looks just like the on I took off my 77 truck a few years ago.

Don't know what kind of HP you will save changing to something else. In a way it depends on which way you go as how much you will save.
I went with a 16 inch E-Fan off Ebay I got for 29 dollars. I use a adjustable thremostate set to kick on at 220. I have a very clean radiator that works well. My fan almost never kicks on. Therfore it save me more Hp and fuel.
The only real downside to E-Fans is there are NO E-fans made that move as much air as the larger Belt driven fans. One of the OEM 7 blade clutch fans will move more Air than youe engine will ever need for cooling.
An E-Fan still has to be powered. No matter what fan you run it will be run from the "Fan'" belt.
You will see a real difference removing the stock fan especally the higher the rpm you twist the engine.

[NumberDummy]

D0SZ-8600-A is another factory flex fan. 5 blade, approx 19" in diameter.

Fits: 1970/79 cars & trucks.

I can't cross reference D7UA-AJA (Ford engineering ID number) to an actual Ford p/n at the moment. Parts catalogs are at home. I'm in TN for the SuperNats.

btw: There's also D6DZ-8600-D, flex fan, 7 blade 17 1/2" diameter, fits all sorts of stuff in the 1960's/1970's.

[unrulee]

When I think Flex fan I think this Summit SUM-G4920 - Summit Standard and High Performance Flex Fans - summitracing.com