4th Gen Rearend

[Billy Nees]

Originally Posted by mtwilly

Greetings! This is my first post, so here goes nothin'! I am building a 1995 Firebird to Stock Eliminator specs. I have noticed when looking at cars that others have built, the rear wheels are nice and deep (shallow offset). To my understanding, the rearend has to be stock width, correct? How are they fitting those wheels in there with a stock width rearend? Thanks, everyone. There will be many more questions to come as I undertake this project

A few year old quote from a DTD, "my boss told me that he had better not see me climbing under cars and measuring rearends anymore". That would lead me to believe that as long as the springs are in the right place and the inner wheel housings aren't modified then you're OK to NOT have a "stock width" rear. Honestly, I don't have a problem with this. If anyone out there would know any different, then I would sure like to know. There IS a new Sheriff in town!

[mtwilly]

Here are some pics of what I am seeing. I'm not really interested in 'breaking the rules' so I am trying to figure out how everyone else is doing it. Glenn, I will definitely keep yours in mind. Right now my cash is going towards a trailer that I will pick up in a week or two.

[KRatcliff]

Since one of those pics is my car I guess I will answer with what I know at the moment. The rear end is a 12 bolt with the stock width and coil spring mounting locations. It has the stock springs and I don't know offhand what the rear wheel offset is, but they are 10" width Weld Alumistars. I don't have any trouble with clearance.

[Rich Biebel]

I had a 4th gen Firebird and it had a KTRE 12 bolt and from what I knew it was stock width. All stock type mounting brackets for suspension and shocks. Pete Z traction bars and lower bars...

I replaced the springs and put stock ones in there to raise it a little.

10" rims and no clearance problems with any 9" tire....

I don't recall the offset but it was nothing unusual....

Hooked in a car wash....LOL

[mtwilly]

Thank you all for the input. I appreciate it. I will see what I can find out for offset on 10" wheels.

[jimmyparker]

The rear ends under these cars are not stock width, a stock width rear end would be too wide. Most of the f body cars I've built had a 60" or so axle flange to axle flange rear end. As mentioned earlier if you have the wheels and tires that will be used on the car you can get a more accurate measurement.

[Race Clean]

Originally Posted by Billy Nees

That would lead me to believe that as long as the springs are in the right place and the inner wheel housings aren't modified then you're OK to NOT have a "stock width" rear.!

This must be the norm!

[CMcAllister]

Typically, one sources the wheels to be used with the desired BS that will be used, throws a set of the largest (or desired size) tires that will be used on them. With no rear in the car, position them under the car in the desired location, measure wheel flange to wheel flange and build the rear to that dimension taking into consideration the brake kit being used, pinion offset, etc. Build the rear to wheels - not the other way around. Typically.

Enough of those cars out there, the dimensions and specs should be standardized with little need to figure it all out yourself.

[kansas stocker]

I was told it needed to be within 1/4" of stock.
Guess it depends on who you ask.
Pete

[2021STK]

for some, asking forgiveness is easier than asking permission.