Driveshaft length

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dustya_383

dustya_383

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What's the drive shaft length for 4speed to 8.75 rear end . My last driveshaft was 727 to 8.75 Can I use this shaft or do I need a longer one? What's the length from yoke to yoke??
 
are you saying measure my driveshaft from my 727 and add another inch ?? to get the length of a 4 speed driveshaft??
 
Does anyone have exact measurements from u joint to u joint?? I hear shaft from a 904 tranny will work but not sure wat rear end it mates to. Don't all rear ends have a different pinion lengths??? I seen someone had measurement posted on the exact length bit can not find the post
 
dustya_383 said:
are you saying measure my driveshaft from my 727 and add another inch ?? to get the length of a 4 speed driveshaft??
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No, measure it w/the 4 gear installed. The 727 yoke should be the same spline as the 4 gear. The 904 yoke will not work as the spline count is different.
 
Correct. So can I put the yoke in to the rear of my trans then measure from that to the diff add an inch to my measurement
 
Do not add anything, subtract. The drive shaft must be shorter than u joint centers. Exactly what car and drivetrain are we talking about?
 
66fs said:
Do not add anything, subtract. The drive shaft must be shorter than u joint centers. Exactly what car and drivetrain are we talking about?
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Ok the car is a 74 duster that had a sb360 with a 727 and an 8.75 Rearend . It now has a 4 speed with the same rear end I'm going to use the same yoke from the 727 shaft. Now I was told the a833 is 4 inches shorter than a 727 . How do I get the correct length.
 
Bottom out the yoke in the trans, pull it out approx. 3/4" to 1". then measure c/l to c/l. You need some play in it for suspension travel.
 
74 valiant with manual transmission, 318 or 360, 8.75 rear 48.96 inches center to center. Use this as a double check, measure as pntastar69 says, sitting full weight on the tires. I would slam the yoke all the way in measure then subtract, that way you only have one measurement and one chance for error. Triple check with you driveshaft shop. Everything makes a difference, you might as well get your driveshaft perfect for your setup.
 
dustya_383 said:
Does anyone have exact measurements from u joint to u joint?? I hear shaft from a 904 tranny will work but not sure wat rear end it mates to. Don't all rear ends have a different pinion lengths??? I seen someone had measurement posted on the exact length bit can not find the post
Click to expand...

There is no "exact" measurement anymore since over the years engine, tranny and rear end mounting could have changed slightly and if they add up to 1/2" shorter or longer then that's to much.
So, do as the guys say, position car on all 4 tires, slide slip yoke into tranny till bottomed, pull out 1", measure from tranny u joint centerline to rear end u joint center line and that's the number your drive shaft assembled should be.
 
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