4th Gen Rearend

Michael K · 09-09-2019, 04:02 PM

Classification guide won't have this info.

The rule book talks about wheel base. Since there are production line assembly tolerances, there is an allowable variation from factory specifications (I can't recall exactly...3/4 inch?). The rear axle width is not addressed, other than stock mounting points and stock width (between backing plates) must be used. I have factory rear housings that vary up to 5/16 inch for the same model of car.

In the spirit of the rules, it would seem that the factory tolerances should be factored in within reason. When asked, division tech would only say that they would not allow stock mounting points to be moved.

Rob Petrie E395 · 11-28-2019, 07:31 PM

Since no one posted it. On a 4 gen F body. If you have a stock length rear end. Using a 10 inch wide wheel you need 7 1/2 inches of back space.

mannymen · 11-28-2019, 10:02 PM

The trick is to use an 82-92 F-Body “STOCK WIDTH” rearend. It’s a complete bolt-in for a 93-02 F Body. The 82-92 is approximately 4” shorter than a 93-02 rearend. This is what u r seeing in the pics u posted. Now you can use a 15x10 wheel with a more common 5.5 backspace.

09-09-2019, 04:02 PM	#1
Michael K Member Join Date: Nov 2012 Location: Minnesota Posts: 101 Likes: 89 Liked 62 Times in 17 Posts	Re: 4th Gen Rearend Classification guide won't have this info. The rule book talks about wheel base. Since there are production line assembly tolerances, there is an allowable variation from factory specifications (I can't recall exactly...3/4 inch?). The rear axle width is not addressed, other than stock mounting points and stock width (between backing plates) must be used. I have factory rear housings that vary up to 5/16 inch for the same model of car. In the spirit of the rules, it would seem that the factory tolerances should be factored in within reason. When asked, division tech would only say that they would not allow stock mounting points to be moved. Last edited by Michael K; 09-10-2019 at 07:38 AM.

11-28-2019, 07:31 PM	#2
Rob Petrie E395 VIP Member Join Date: Dec 2007 Location: Woodlawn IL Posts: 1,092 Likes: 162 Liked 216 Times in 77 Posts	Re: 4th Gen Rearend Since no one posted it. On a 4 gen F body. If you have a stock length rear end. Using a 10 inch wide wheel you need 7 1/2 inches of back space.

11-28-2019, 10:02 PM	#3
mannymen Senior Member Join Date: Apr 2003 Posts: 728 Likes: 5 Liked 13 Times in 7 Posts	Re: 4th Gen Rearend The trick is to use an 82-92 F-Body “STOCK WIDTH” rearend. It’s a complete bolt-in for a 93-02 F Body. The 82-92 is approximately 4” shorter than a 93-02 rearend. This is what u r seeing in the pics u posted. Now you can use a 15x10 wheel with a more common 5.5 backspace. __________________ N/A