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Discussion Starter #1
My car currently has an 8 inch in it, with 2.79 gears... This summer I came across a 9 inch, which I took apart to find a 4 pinion 28 spline tack lok in it, and a set of 3.23 gears. Google tells me the tack lok will fit in to my 8 inch, but I was wondering if anyone could tell me if a 9 inch set of gears will fit a 8 inch? The axles are interchangeable I have been told, so the theory would be to do a straight gear swap and toss the track lok in and save myself cutting the 9 inch to fit.
 

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What did the 9 inch come out of? I say just put the 9 inch in the car and go from there instead of messing around swapping parts to make it fit the 8 inch.

thanks
pat
 

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8-inch and 9-inch traction loc units are NOT interchangeable! The carrier unit is made for either the 8" or 9" ring gear.
 

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Discussion Starter #4
The 9 inch came out of a 70's lincoln continental, which had a 460 in it, probably the reason it had the tack lok. But yeah, google tells me that some of these lincolns had a 9 3/8 diff, which is similar, but still slightly different... So I can't even really say if its a 9 inch or not, because the pictures I see of the two make them out to look identical in my eyes. Either way though, I think the gears fit both 9's, so I guess I could always cut it down anyways and stick it in, seeing as I have all the parts from it still anyways.
 

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Was the Lincoln rearend set up for coil springs? If so, lots of differences beyond just the width of the rear. I'm also a little surprised you'd find a traction lok in a Lincoln. Depending on your budget, you may want to consider an aftermarket center section for the 8". Or dig up a 9" housing for a mustang/cougar. I think anything 67-70 will work but double check the width. I do believe the axles will interchange.
 

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8" and 9" are a lot different. I bought a used 9" out of a bronco and had it narrowed. I probably could have done it myself but i went ahead and took it to a shop that had a jig to do it. They only charged me $100 and it turned out perfect. I want to say I had it narrowed to 53" overall length but I can't remember. When I had it narrowed and the center section rebuilt I took it down and had custom 31 spline axles made to fit. Overall, it saved me about $1000 between buying a currie rear-end. If you look on craigslist you can probably find a 9" for $100. Thats how much I paid for mine. I have a small album in my profile that shows some pics that way you can identify 9" between 8".
 
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