8 or 9 inch diff

S

Smash It Up

New Member

Oct 26, 2007

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Las Vegas,nv

Nov 23, 2007

#1

• Nov 23, 2007

• #1

The diff on my car has a bulge ,slightly off centered,in the front facing part. Also the axles taper slightly about 2/3 of the way along toward the hub on each side. I read that this is the 9 inch?
Would this have been retrofitted or orignal to the car? I don't know if it would have been an option or not. Can I tell from the VIN ?
thanks

 

zookeeper

Founding Member

Aug 25, 2001

3,415

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109

Rogue River, Oregon

Nov 23, 2007

#2

• Nov 23, 2007

• #2

The quick and dirty way to tell a 9 from an 8 is to look at the bottom two bolts that hold the gear carrier in place. If you can get a socket on them, it's an 8 inch, if you have to use an end wrench, it's a 9 inch. Without knowing what year of car, what motor it came stock with, etc there's no way to know if it came stock in the car. The tapered axle housings don't really tell you much, since the stock 8 inch in my old '65 fastback had them as well.

 

S

Smash It Up

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Oct 26, 2007

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Las Vegas,nv

Nov 23, 2007

#3

• Nov 23, 2007

• #3

69 fastback 351w FMX auto. But isnt there a way to tell from the VIN or some other code that can tell me what it was meant to have originally?

 

D

danny clemens

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May 4, 2005

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Nov 23, 2007

#4

• Nov 23, 2007

• #4

If it's an original 351W (5th digit of the vin being an M or H) then it's a 9" that is if it's the original rear.

 

S

Smash It Up

New Member

Oct 26, 2007

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Las Vegas,nv

Nov 23, 2007

#5

• Nov 23, 2007

• #5

Oh ok. Yeah it is an H code. Thanks for clearing that up !!