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4th gen 9in swap into a 3rd gen?

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Old Jun 24, 2025 | 05:13 AM
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4th gen 9in swap into a 3rd gen?

A guy close to me is selling a Quick Performance 9in housing for a 4th gen F Body. Would I be incorrect in believing I could bolt that into a 3rd gen? Would it be much different than swapping a 4th gen rear end into a 3rd gen? It has the backing plates for the ls brakes.

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Old Jun 24, 2025 | 05:49 AM
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Car: 86 trans am
Engine: 383 w true duals
Transmission: t56
Axle/Gears: 3.73
Re: 4th gen 9in swap into a 3rd gen?

its pretty much bolt on youd just need to reroute the parking brake, and the rear is a little wider i think a inch and a quarter, so youd want spacers in the front
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Old Jun 24, 2025 | 07:45 AM
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Re: 4th gen 9in swap into a 3rd gen?

Originally Posted by sscooter
its pretty much bolt on youd just need to reroute the parking brake, and the rear is a little wider i think a inch and a quarter, so youd want spacers in the front
Thats what I thought but wanted to be sure. Thanks!
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Old Jun 24, 2025 | 08:17 AM
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Re: 4th gen 9in swap into a 3rd gen?

The Torque arm design is a little tricky with the QP unit. Is that included in the sale, you'll need the bracket for that rear. Also, the sides of the rear will be about 1.5" wider per side than the 3rd gen 10 bolt but will otherwise bolt right in.
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Old Jun 25, 2025 | 12:25 AM
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Re: 4th gen 9in swap into a 3rd gen?

Originally Posted by ShiftyCapone
The Torque arm design is a little tricky with the QP unit. Is that included in the sale, you'll need the bracket for that rear. Also, the sides of the rear will be about 1.5" wider per side than the 3rd gen 10 bolt but will otherwise bolt right in.

it will come with the bracket for the torque arm, but I’m actually thinking about going a slightly different route. There’s a guy selling a complete 8.8 with the entire brake package that he pulled from a 4th gen. Just waiting to hear back from him. The 9 inch has 35 spline axels, I’ve only found 1 35 spline 3rd member and it’s got a spool. I’m sure if I looked harder I could find a 35 spline 3rd member with an LSD.

This car will rarely if ever see a strip so I’d rather have a LSD, plus by the time I buy this housing, a 3rd member and 31 spline axels I could just bolt in the 8.8 and be in it for less money.
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Old Jun 25, 2025 | 01:36 AM
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Re: 4th gen 9in swap into a 3rd gen?


Can anyone tell if this is a Hawks unit or a diy?
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Old Jun 25, 2025 | 06:55 AM
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Re: 4th gen 9in swap into a 3rd gen?

Plenty of LSD options for either rear. S-trac, tru-trac, ect.
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