Mini tubbing my Duster

[SSG_Karg]

Well, I’ve decided to start the process of mini tubbing my Duster. I’ve always loved the look of big fat tires under the rear of just about any muscle car and now I have enough motor to actually warrant having them.
The project started with picking up a bare 8.75 housing locally for $50. It’s a 71-74 B-body rear so she’s wiiiide! I’ve only taken some rough measurements so far but I’ll likely be taking at least 3 inches off of each side.
Next I found a sweet pair of 15x10 Centerline AutoDrags that will match my current wheels so I will be able to switch between slicks and radials as needed. Found those on Facebook only about 1.5 drive away.
Then I picked up a USCT spring relocation kit from a member here.
So far the rear had been stripped and is ready to chop. I plan to cut the inner tubs out so I can set the wheels and tires in place and take some good precise measurements before cutting the housing. I plan to order new axles from Dr Diff and I will reuse the center section that is currently in the car. It’s a 489 case with 3.91 Sure Grip.
The tires that I have on the wheels right now are 29.5x10.5W but I may swap them out for a 28x10.50W eventually.

I will try to document my progress on this thread as it plays out. Please feel free to add your thoughts and advice as this is my first time narrowing an axle or mini tubbing a car. Im sure I’ll have some questions along the way.

As you can see, we’re gonna need to make some room in there in order to tuck these bad boys into the quarters.

 

[69conv]

Kool project, looking forward to the finished product! How are you working the exhaust?

 

[SSG_Karg]

Kool project, looking forward to the finished product! How are you working the exhaust?

I’m still running a stock gas tank so initially I’ll probably just put some turndowns on the end of the mufflers. Eventually it will probably get a fuel cell in the trunk and exhaust run out the back as close to stock as possible.

 

[69conv]

If you angle the turndowns towards the center it wont blow as much dust out the side when you idle along. Some have said its a bit quieter too.

 

[33IMP]

If you angle the turndowns towards the center it wont blow as much dust out the side when you idle along. Some have said its a bit quieter too.

I did that on my strip-street car. Really liked the result, recommend to anyone using turndowns in front of axle.
Ssg Karg, did you trim the front of the wheelwells to get the 29.5s to clear? Moving the axle back as part of the mini-tub is also possible.

 

[SSG_Karg]

Ssg Karg, did you trim the front of the wheelwells to get the 29.5s to clear?

Yes, they were trimmed about 1.5” way back in 2001 when the car was painted.

 

[MOPARMAGA]

Well, I’ve decided to start the process of mini tubbing my Duster. I’ve always loved the look of big fat tires under the rear of just about any muscle car and now I have enough motor to actually warrant having them.
The project started with picking up a bare 8.75 housing locally for $50. It’s a 71-74 B-body rear so she’s wiiiide! I’ve only taken some rough measurements so far but I’ll likely be taking at least 3 inches off of each side.
Next I found a sweet pair of 15x10 Centerline AutoDrags that will match my current wheels so I will be able to switch between slicks and radials as needed. Found those on Facebook only about 1.5 drive away.
Then I picked up a USCT spring relocation kit from a member here.
So far the rear had been stripped and is ready to chop. I plan to cut the inner tubs out so I can set the wheels and tires in place and take some good precise measurements before cutting the housing. I plan to order new axles from Dr Diff and I will reuse the center section that is currently in the car. It’s a 489 case with 3.91 Sure Grip.
The tires that I have on the wheels right now are 29.5x10.5W but I may swap them out for a 28x10.50W eventually.

I will try to document my progress on this thread as it plays out. Please feel free to add your thoughts and advice as this is my first time narrowing an axle or mini tubbing a car. Im sure I’ll have some questions along the way.
View attachment 1716374183

As you can see, we’re gonna need to make some room in there in order to tuck these bad boys into the quarters.
View attachment 1716374184View attachment 1716374185
View attachment 1716374186

In my opinion the tires look great where they are
But I see your on Jack stands and you don't have a dart to do super stock wheel well arches.
Are the m/t 29.5s actually that size ?
My hoosiers are 30.6 but called 29.5

 

[Oldmanmopar]

15x12 wheels with 7 1/2 back space with a factory width rear. Tires are 29x14.5 . only added a 3 inch inboard kit.

 

[racerjoe]

Well, I’ve decided to start the process of mini tubbing my Duster. I’ve always loved the look of big fat tires under the rear of just about any muscle car and now I have enough motor to actually warrant having them.
The project started with picking up a bare 8.75 housing locally for $50. It’s a 71-74 B-body rear so she’s wiiiide! I’ve only taken some rough measurements so far but I’ll likely be taking at least 3 inches off of each side.
Next I found a sweet pair of 15x10 Centerline AutoDrags that will match my current wheels so I will be able to switch between slicks and radials as needed. Found those on Facebook only about 1.5 drive away.
Then I picked up a USCT spring relocation kit from a member here.
So far the rear had been stripped and is ready to chop. I plan to cut the inner tubs out so I can set the wheels and tires in place and take some good precise measurements before cutting the housing. I plan to order new axles from Dr Diff and I will reuse the center section that is currently in the car. It’s a 489 case with 3.91 Sure Grip.
The tires that I have on the wheels right now are 29.5x10.5W but I may swap them out for a 28x10.50W eventually.

I will try to document my progress on this thread as it plays out. Please feel free to add your thoughts and advice as this is my first time narrowing an axle or mini tubbing a car. Im sure I’ll have some questions along the way.
View attachment 1716374183

As you can see, we’re gonna need to make some room in there in order to tuck these bad boys into the quarters.
View attachment 1716374184View attachment 1716374185
View attachment 1716374186

I'd go with something other than Dr. Diff axles if you're putting down any kind of power with slicks.

 

[Oldmanmopar]

That car looks familiar

 

[SSG_Karg]

15x12 wheels with 7 1/2 back space with a factory width rear. Tires are 29x14.5 . only added a 3 inch inboard kit.

View attachment 1716374229

View attachment 1716374230

View attachment 1716374231

View attachment 1716374232

I can’t believe how clean those wheel tubs look. They look like they left the factory that way. Very nice fabrication work.

 

[davescuda]

my 2 cents. Leave the outer part of the frame rail and but the box up against it. Also if you can cut out the bump in the out wheelhouse out would be nice. Things I wish I did. Barracuda has the same wheel well
390/45/15 with factory gas tank and tail pipes

 

[SSG_Karg]

Leave the outer part of the frame rail and but the box up against it.

Wouldn’t that make the leaf springs out of square? The springs would be narrower in the front. I haven’t measured yet but I am assuming that the frame rails are parallel from the front to rear. What would be the benefit of leaving the outer part of the rail?

 

[SSG_Karg]

I'd go with something other than Dr. Diff axles if you're putting down any kind of power with slicks.

I’ll at least talk to Cass about it before putting my money down. Motor probably only makes 450-500hp. 99% street car but it is a 4 speed and I like to punish it. If he doesn’t have a warm and fuzzy about I will step up to Moser or Strange.

 

[SSG_Karg]

Barracuda has the same wheel well
390/45/15 with factory gas tank and tail pipes

Beautiful car! Those tires are YUUUGE! I’m gonna try to tuck mine in just a little more than that.

 

[davescuda]

Wouldn’t that make the leaf springs out of square? The springs would be narrower in the front. I haven’t measured yet but I am assuming that the frame rails are parallel from the front to rear. What would be the benefit of leaving the outer part of the rail?

No you put them in the frame just leave the outer skin if that makes sense. You never actually cut the whole frame out(most of it)

 

[davescuda]

Beautiful car! Those tires are YUUUGE! I’m gonna try to tuck mine in just a little more than that.

Its just the look for now. I plan in the future is to tuck a smaller tire in.

 

[crackedback]

Sent the powerpoint and some other stuff. Take your time, think before you cut is the biggie. The old carpenter joke, I cut it three times and it's still too short...

Be patient and no ugly *** floor patches

 

[SSG_Karg]

53 years of undercoating and burnt rubber. About 5lbs worth.

 

[RustyRatRod]

Heck, I like the tires sticking out from under the quarters look! lol

 

[MOPARMAGA]

Heck, I like the tires sticking out from under the quarters look! lol

Yeah, it looks great.

 

[v8dve]

Sent the powerpoint and some other stuff. Take your time, think before you cut is the biggie. The old carpenter joke, I cut it three times and it's still too short...

Be patient and no ugly *** floor patches

Hi Crackedback, would you be able to send me a copy too as soon to minitub mine, and need as much info as possible.

Many thanks

 

[SSG_Karg]

There’s factory paint under all that grime and rubber! What color would you say that is? Y8 Gold Leaf Poly? No fender tag or build sheet for this car.

 

[crackedback]

What was the line from "Used Cars"
Is this a taxi?
No, that's yellow primer...

Looks like gold to me.