Clutch Fan

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So, does anyone know the length of the clutch shaft for the big block Dart?
 
FWIW, in '69, my parts book don't list a BB drive. I'm guessing '68 may be similar...........

Dart is above green arrow............

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Ok, a bit of an update. A member from another site gave me a Hayden part number of P/N 2947. Looked it up and its designed for cars with limited space due to over sized radiators. Gives almost 3" of additional clearance between the rad and the water pump. I'll post as soon as I get it mounted.
 
dart4forte said:
Ok, a bit of an update. A member from another site gave me a Hayden part number of P/N 2947. Looked it up and its designed for cars with limited space due to over sized radiators. Gives almost 3" of additional clearance between the rad and the water pump. I'll post as soon as I get it mounted.
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u sure that aint 3/4" ?? no way 3" !
 
dart4forte said:
No Bob, you go back and read, I said almost!! Can we say petty argument?
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ur missing my point, putting a clutch type fan will take up that much clearance , not give it . I don`t even have but 3 1/4" w/o a fan at all.
 
I have right at 2 7/8" from the core to the pulley and the 2947 clutch is 2.67" how close is to close? I am going to check the fan tips to core to see if it is square if not that is a deal killer.
 
MP recommends .750" clearance. A lot of folks might push it to .500" I believe.
 
I’ve said it before, the radiator has to move back if your gonna run a clutch fan. That involves some cutting, and I’m sure a lot of people don’t want to go that, so that leaves 2 options. Run a fixed or a pusher fan combo.
 
famous bob said:
ur missing my point, putting a clutch type fan will take up that much clearance , not give it . I don`t even have but 3 1/4" w/o a fan at all.
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I guess proof is in the pudding. I'll have the new clutch this afternoon. I'll put it in tomorrow and take some measurements.
 
I’m pretty sure damn sure that clutch isn’t gonna fit. Go with a fixed fan/spacer and shroud. Or move the radiator back and gain the much needed clearance for either a clutch fan or electric fan(s).
 
5.7 hemi said:
I’ve said it before, the radiator has to move back if your gonna run a clutch fan. That involves some cutting, and I’m sure a lot of people don’t want to go that, so that leaves 2 options. Run a fixed or a pusher fan combo.
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There's no need to move the radiator to run a fan clutch. You've just gotta buy a fan clutch that fits.
 
BS! The Hayden 2947 is THE shortest fan clutch made, it’s still not short enough to run in an A body with a big block. I know, I tried. You got a small block, your golden. Otherwise fixed fan/spacer or move the radiator back to run electric fan(s) or clutch.
 
I don't know what all the argument is... i was informed by a reputable radiator owner who only runs a HAYDEN FLEX fan with his 1000 hp engine at track and street driven , with metal radiator with NO issues ... You need to make sure it is orientated correctly in shroud ..
 
We are discussing clutch fans and why they don’t fit. It’s really not the fan, it’s the clutch, thermal or viscous, they don’t fit.

I’m not arguing, more of trying to save people the aggravation of doing what I and others went through only to find out they won’t fit. Just trying to help everyone out.
 
5.7 hemi said:
BS! The Hayden 2947 is THE shortest fan clutch made,
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Wrong again... The 2765 clutch is a touch shorter since it doesn't have the HD fins in front. Granted, this clutch isn't designed for the heavier steel fan blade, though many use it them with it with no problems.

You oughta do a search on bigblockdart.com. There are plenty of folks running fan clutches on BB A-bodies with radiators in the stock location- several of whom are on this site too.

To the OP- don't be afraid of .250"-.375" of radiator-clutch clearance. Just run some sort of motor forward/aft limiter or a thru bolt thru the DS motor mount and you'll be fine.
 
You better double check your numbers. You are wrong.
 
5.7 hemi said:
You better double check your numbers. You are wrong.
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What numbers? The 2974 clutch uses the exact same shaft as the Jag clutch (2765). Well, they did in the first design. They have since increased the OD of the water pump mount flange; But the length is the exact same. The only difference between the two is that the 2947 clutch uses the HD clutch body.
 
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