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8" to 9" break-in question

  • Thread starter Thread starter JC6715
  • Start date Start date May 31, 2008

JC6715

Member
Oct 24, 2005
284
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Hillsboro, Oregon
May 31, 2008
#1
  • May 31, 2008
  • #1
I am going to be swapping out the entire drivetrain (old- 289 C4, 8" rear) for new stuff (331, T56, 9" rear). I was hoping to be able to break in the new rear gears in the 9" using the old 289 and C4...

EXCEPT, the driveshaft is looking like it might be too long... How much clearance does it need to have before bottoming out to run for roughly 200-300 miles (long enough to break in the gears)? I'll be getting a new custom shaft when I put in the new engine and trans...

Could I jerry rig the transmission side yoke and just cut off about 3/4s to an inch? Keep in mind it will only be driven like that for about 300 miles, and will be babied to break in the gears...

What do you all think?
 
D

D.Hearne

New Member
Sep 29, 2000
11,730
6
0
south louisiana
May 31, 2008
#2
  • May 31, 2008
  • #2
You need at least an inch of room in the transmission tail for the yoke movement. But as long as you baby it, I doubt you'll have a problem.
 
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