General rad fan question for my 56

[samdjr74]

Hi All,

I need to get a fan for my radiator. I'm running a 350 pushing around 400hp, a 700R4 behind it and the radiator is a 4 core aluminum with the trans cooler built in. My question is, is there a rule of thumb on how many CFM's my fan should be pulling per HP or displacement? I don't have A/C in the truck now but I might sometime down the road. The issue I'm running into is the space between the pulley and the radiator is very tight, a little over 3" so I'm limited to what I can do. I found 1 dual electric puller but it's only 1600CFM's and I'm a little worried that it might no be enough. Any help would be great.

Thanks,
Sam

[GCncsuHD]

1600 is definitely low. That is plenty for a stock manual SBC, but with 400HP and an Auto I would look closer to 2500+, if you would be adding AC you are going to want to add another 1000CFM just for that. Whatever you do, build a shroud for it to be the most efficient, all the CFM in the world isn't worth a thing if it's not utilizing all of the radiator's area.

[55metalmonkey]

dumb question but are you running with a shroud and mechanical fan? without the shroud the fan would move much less air through the rad.

I agree, 1600 cfm seems a bit low, bigger better IMO (in most cases)

[samdjr74]

Not a dumb question at all. If I was going with a mechanical fan then yes or even a single electric fan, I would use a shroud. But I'm looking at dual electric fans that have the built in shroud that covers the entire radiator.

My problem right now is the size. The radiator isn't for a 56, not sure what it's for, it was sold as a 55-59 and I go it real cheap but it's new and aluminum so I plan to use it. But the radiator itself is 25 1/2" wide with 1 1/2" mounting bracket on each side for an electric fan. It's 16" tall for the core area and 21 1/4" overall high. The problem is the distance between the radiator and the bolts on the water pump pulley, I only have 3 3/8" between the 2. So far finding a fan that will fit is a little tough.

Originally Posted by 55metalmonkey

dumb question but are you running with a shroud and mechanical fan? without the shroud the fan would move much less air through the rad.

I agree, 1600 cfm seems a bit low, bigger better IMO (in most cases)

[55metalmonkey]

Don't know it it would fit since I don't have my rad and core support in yet but a pair of pusher fans might be an option
might be worth looking into

[samdjr74]

I was thinking about that too, there seems to be room between the radiator and the support for a couple of pushers.

So far I think I might go with this model

http://www.summitracing.com/parts/DER-16928/

Originally Posted by 55metalmonkey

Don't know it it would fit since I don't have my rad and core support in yet but a pair of pusher fans might be an option
might be worth looking into