Driveshaft Balance?

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pastortom1

pastortom1

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Guys......... I'm working on a 74 Dart Sport 360 clone.........

It's now a 360 to 727 to 8-1/4..........They shortened the driveshaft from the looks of it, and it feels a little out of balance.........we just changed the universals..........bad............we think the imbalance knocked them to hades.........

Anyone have a driveshaft for this car?............Need a stock factory shaft asap...........(a GOOD one)..............

The vibration is harmonic, and is definitely in the rear where the yoke was welded........... :angry7:
 
..............we mean the vibration is definitely in the REAR..........I suppose there's a chance it could be something else, but we highly doubt it after looking at the condition of the U-Joints............:read2:
 
Did you check it for runout with an indicator in the front, middle and rear?
 
pastortom1 said:
Guys......... I'm working on a 74 Dart Sport 360 clone.........

It's now a 360 to 727 to 8-1/4..........They shortened the driveshaft from the looks of it, and it feels a little out of balance.........we just changed the universals..........bad............we think the imbalance knocked them to hades.........

Anyone have a driveshaft for this car?............Need a stock factory shaft asap...........(a GOOD one)..............

The vibration is harmonic, and is definitely in the rear where the yoke was welded........... :angry7:
Click to expand...


Pastor, what do you mean "your yoke was welded".

Terry
 
I just looked at the driveshaft chart on another thread, and cannot find a listing for a 360-727/8-1/4 combo on the Dart Sport in 74.........

SO, back to my original thought, I believe to change the trans to the 727 would mean a shorter driveshaft.....correct? If so, it would seem logical, considering where the vibration IS on the car, and considering the shape the rear U-Joint was in, that the shaft was not welded true..........if the rear yoke is off just a squeak, it will vibrate harmonically, and wear out the joint pretty fast.......... Correct?

Opinions? :read2:
 
When i had my drive shaft shortened it would start vibrating around 65 MPH.
I took it back to where it was balanced and on the second try it no more vibration. I would take it back and have it rebalanced to whoever shortened the shaft for you.
 
So, for the bottom line in all of this, when you change from a 904 to a 727, do you have to shorten the driveshaft?

Yes? No? :read2:
 
Balance it. I had mine done. They supplied and installed 2 new u-joints and charged me $110.00.
 
For that price range, it sounds like it would be a wise choice............

But I'd still like to know for future reference if the shaft needs to be shortened when you change from a 904 to a 727...........????? (I should know this, but since I'm a lot older than the cars, I'm exempt.....kinda like an odometer....you get to a point where it just don't matter).

I'm sure with the number of A-Body's I plan to do that I'll run into this again.......In fact, my last Demon was a 904 with an 8-3/4 behind it.......If I had hung on the car, I was planning a swap for a worked 727........:toothy10::toothy10::toothy10::toothy10::toothy10::toothy10:
 
pastortom1 said:
For that price range, it sounds like it would be a wise choice............

But I'd still like to know for future reference if the shaft needs to be shortened when you change from a 904 to a 727...........????? (I should know this, but since I'm a lot older than the cars, I'm exempt.....kinda like an odometer....you get to a point where it just don't matter).

I'm sure with the number of A-Body's I plan to do that I'll run into this again.......In fact, my last Demon was a 904 with an 8-3/4 behind it.......If I had hung on the car, I was planning a swap for a worked 727........:toothy10::toothy10::toothy10::toothy10::toothy10::toothy10:
Click to expand...

I am going to say yes, a 904 is shorter than the 727. But when I get home tomorrow I'l measure both and let you know. I right there with you on the age thing, my memory is getting so bad. But on the plus side, I plan on being able to hide my own Easter eggs next year!
 
pastortom1 said:
So, for the bottom line in all of this, when you change from a 904 to a 727, do you have to shorten the driveshaft?

Yes? No? :read2:
Click to expand...

Yes. I don't remember how much shorter the 904 is but it is shorter so to use the same shaft on a 727 would require it to be shortened.
 
Tom, Advance Driveline in Orlando can do it for you, it may need to be cut off and rewelded though. They are on Carder Rd which is just north of Lee Rd and Orange Blossom Trail.
 
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