Clutch style fan

[MaximusB]

I have a 1983 Chevy k20 with a 350sb that I built up and it has a three blade clutch fan on it and I would like to stick with a clutch fan but want to get atleast a five blade and can't seem to find one anyone know one that would fit?

 

[carfanatic63]

I would measure your current fan and order another fan in same diameter. Since SBC are everywhere, most universal fans have the bolt pattern to fit the water pump pulley. I did this when upgrading to a serpentine system on my truck while keeping mechanical fan (spins other way in serpentine set up)

 

[Matt69olds]

I have never seen a fan with a clutch h that has only 3 blades.

5 and 7 blade fans should be fairly easy to locate I would think. GM made millions of these trucks, parts should be easy to find.

 

[DoubleDingo]

Check ebay. I ordered mine off of there.

 

[fast 99]

I have never seen a fan with a clutch h that has only 3 blades.

5 and 7 blade fans should be fairly easy to locate I would think. GM made millions of these trucks, parts should be easy

Keep in mind depending on the clutch the fan may be noisy at times. I took off a 5 blade and installed a 3 blade to quiet it down. Drove the truck 200k towing cars all over the county in all weather. It never overheated. Would not recommend doing that with an AC equipped truck.

 

[Matt69olds]

The thermal fan clutch on all my vehicles is a little noisy when you first start the engine, after a few seconds it quiets down to where you can’t hear it.

You can definitely hear the fan roar when the clutch engages, I suppose that’s a good thing. There is no question the fan is doing what it’s supposed to

 

[75gmck25]

Foremost years you can get three versions of the clutch - standard, heavy duty and severe duty. Haynes used to publish the specs for the % of engagement of the clutch at various temp levels. I use a severed duty on my K75 and don’t notice any excessive noise.

 

[nvrenuf]

Noisy lol. That’s the sound of your truck not overheating.

I’ve always run severe duty clutches on my big blocks. There used to be a part number specific to 4.56 geared trucks that stayed engaged longer because they lived at a higher rpm during low speeds, I haven’t seen that footnote in a while though. I want one like that for my current serpentine belt set up.

 

[AuroraGirl]

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sbc 3 vs 7 blade

Keep in mind depending on the clutch the fan may be noisy at times. I took off a 5 blade and installed a 3 blade to quiet it down. Drove the truck 200k towing cars all over the county in all weather. It never overheated. Would not recommend doing that with an AC equipped truck.

i think depending on the blade size and pitch the fan with less blades tends to be louder, but I could be wrong. the fan clutch itself will determine this a lot. a cheap duralast fan clutch vs an oem quality will be world difference

 

[fast 99]

I have both those fans on different trucks. The bottom one is noisy especially at start up and when first entering freeway speeds.

nvrenuf, it's a totally different world with a big block. Was only suggesting that a 3 blade on a small block without AC worked. After owning many 454's I know they need much more cooling. Would not consider that at all.

 

[nvrenuf]

I was talking about the clutches, not the fans. I only run 7+ blades on my 454’s.

 

[MaximusB]

I ordered a 7 blade universal one that was the same dimesnsions

 

[Rusty Nail]

I ditched a 5 blade for a 7 and like it better.