69 12 bolt chevy diff into 67 gto 4 speed - Pontiac GTO Forum
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post #1 of 8 (permalink) Old 01-21-2014, 10:32 PM Thread Starter
 
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69 12 bolt chevy diff into 67 gto 4 speed

Hi Guys what parts will I need to install 12 bolt diff from a 69 chevelle into my 67 GTO 4 speed I have the drive shaft from the chevelle it had the same 4 speed any help or info would be helpful
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post #2 of 8 (permalink) Old 01-22-2014, 12:32 AM
 
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That rear is 5/8" wider each side than the 66/67 GTO, so you have to have bigger offsets or stock rims. I use the 66/67 rears in my 70 to get the narrower rear end. Driveshaft should work, but tires may hit fenders. Best of luck.

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post #3 of 8 (permalink) Old 01-22-2014, 05:06 PM Thread Starter
 
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Originally Posted by jetstang View Post
That rear is 5/8" wider each side than the 66/67 GTO, so you have to have bigger offsets or stock rims. I use the 66/67 rears in my 70 to get the narrower rear end. Driveshaft should work, but tires may hit fenders. Best of luck.
I have 15 '' rims on gto now that makes it worse
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post #4 of 8 (permalink) Old 01-22-2014, 07:55 PM
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Consider maybe trading for the correct year.

Or run the offset wheels.

Do you have over 5/8" clearance now? I would say minimum should be 1/2" or 5/8" after you install the new rear so you should have at least 1 1/8" per side now or you'll chance rubbing.

You could "roll" the fenders to gain additional clearance. Many will "poo poo" this idea but if done right it will not damage your paint and be virtually unnoticeable.

So I would measure first and then decide if you don't have enough clearance to-
1. Trade the rear.
2. Offset wheels.
3. Roll or clearance fenders.
4. Keep your stock rear and upgrade the axles, diff and gears to be damn near as stout as a stock 12 bolt. Remember......stock 12 bolt Chevy's have their weak points too.
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post #5 of 8 (permalink) Old 01-23-2014, 05:58 PM
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Originally Posted by ALKYGTO View Post
...You could "roll" the fenders to gain additional clearance...
Alky, your fenders must be better than mine. Mine don't roll worth beans. They just sort of rock back and forth on the ground...

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post #6 of 8 (permalink) Old 01-24-2014, 12:52 PM
 
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I believe you will need a specialized u-joint that goes from Chevy to Pontiac. Ames sells them, but you can probably get them anywhere
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post #7 of 8 (permalink) Old 01-25-2014, 10:46 AM
 
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I have a 71 12 bolt in my 66 so should be the same. I run 265/60/15 and have used the 7" & 8" rallye one wheels. I forget the exact offset, but they are the ralleys that Ames a d summit sell, so you could look up the offsets offered in those wheels. I am thinking the 7 wheel is a 4" offset and the 8" is a 5" offset.

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post #8 of 8 (permalink) Old 01-26-2014, 05:27 AM Thread Starter
 
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I have a 71 12 bolt in my 66 so should be the same. I run 265/60/15 and have used the 7" & 8" rallye one wheels. I forget the exact offset, but they are the ralleys that Ames a d summit sell, so you could look up the offsets offered in those wheels. I am thinking the 7 wheel is a 4" offset and the 8" is a 5" offset.

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thanks guys
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  Pontiac GTO Forum > The 1964-1974 Pontiac Tempest, Lemans & GTO > 1964-1974 Tempest, Lemans & GTO Undercarriage, Frame, Transmission and Differential Discussions.

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