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#2461289 - 03/04/18 10:46 PM What rearend for turbo car?
moparmafia Offline
mopar

Registered: 01/01/07
Posts: 532
Loc: Ky
I am building another turbo car and trying to decide what rear to put under it. I have a 340 demon with a turbo and 8 3/4 with 3.23 gears i drive alot and i think it would be even quicker with 2.91 . this other car will be indy headed 440 with twin turbos so the 8 3/4 is out of the question. the only dana 60 gears i see are 3.54 gears and thats too low. I dont like the idea of running a 9 inch unless i have no other options. I want something around 3.08 or 3.23. what would be my best option to keep it all mopar?

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#2461302 - 03/04/18 11:01 PM Re: What rearend for turbo car? [Re: moparmafia]
Twostick Offline
master

Registered: 05/20/03
Posts: 4924
Loc: Downtown Roebuck Ont
A Dana 61 out of a first gen Diesel Dodge could be had with 3.07 gears.

Kind of like a Dana 60 but without the aftermarket support.

How heavy is the car?

Kevin

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#2461350 - 03/05/18 04:16 AM Re: What rearend for turbo car? [Re: moparmafia]
TRENDZ Offline
top fuel

Registered: 01/24/05
Posts: 1651
Loc: Milwaukee WI
The dana being referred to is actually a 71. No real good parts available for it.

I would (and have) gone with the strange ultra case. The standard ultra case takes a true 9” gear, but the pinion shaft can be upgraded to a large 35 spline configuration. This particular setup will allow down to a 3.40 ratio. If you upgrade to the 9.5” gear set, you can get a ratio as low as 3.2. These are pro gear sets.
Running low ratios is extremely hard on everything in front of the rear end. Plan on spending a whole lot on trans parts.
_________________________
"use it 'till it breaks, replace as needed"

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#2461357 - 03/05/18 06:13 AM Re: What rearend for turbo car? [Re: moparmafia]
dizuster Offline
master

Registered: 01/12/05
Posts: 3337
Loc: Oakland, MI
I agree...as die hard mopar as i am...the 9" is your best bet if you need a gear that low in ratio.

Either that or taller tire/more cam/more mph/RPM.
_________________________

Owner of the ugliest turbo car on the planet. 9.55-141.8mph @3740lbs on 275's

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#2461578 - 03/05/18 02:38 PM Re: What rearend for turbo car? [Re: TRENDZ]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 30807
Loc: Bend,OR USA
Originally Posted By TRENDZ
The dana being referred to is actually a 71. No real good parts available for it.

I would (and have) gone with the strange ultra case. The standard ultra case takes a true 9” gear, but the pinion shaft can be upgraded to a large 35 spline configuration. This particular setup will allow down to a 3.40 ratio. If you upgrade to the 9.5” gear set, you can get a ratio as low as 3.2. These are pro gear sets.
Running low ratios is extremely hard on everything in front of the rear end. Plan on spending a whole lot on trans parts.

Dana makes the 61,71 and maybe even the 81 series with the 3.54 and higher sped ratios. The 61 first came in the Ford 3/4 ton trucks with a 3.30 ratio, later in the Dodge pickup CTD trucks as already mention with the 3.30 and 3.07 up scope
One of the local scrap yards has both, maybe I should scoop both of them up for future builds work
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2461592 - 03/05/18 03:00 PM Re: What rearend for turbo car? [Re: moparmafia]
TRENDZ Offline
top fuel

Registered: 01/24/05
Posts: 1651
Loc: Milwaukee WI
The only CTDs that had a 61 axle were the “W” (4wd) and they were front axles. All pre overdrive CTDs had rear 71s otherwise known as D70U. The only difference from a standard 70 was an internal “U”ndercut for the large pinion gear tooth clearance. Not a good rear for performance by any means. The reason I know this is I have seen more than my fair share, and had to source parts for them.😉
_________________________
"use it 'till it breaks, replace as needed"

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#2461632 - 03/05/18 04:36 PM Re: What rearend for turbo car? [Re: moparmafia]
dizuster Offline
master

Registered: 01/12/05
Posts: 3337
Loc: Oakland, MI
I tried to find something shallower then a 3.54 for my car. The rare 3.30 and 3.07 stuff is hard to find, and if you break one good luck finding another one.

I just gave up and went with the 3.54. It's not bad...142mph on 28" and only crosses around 6500.

If you're starting from scratch just go 9".
_________________________

Owner of the ugliest turbo car on the planet. 9.55-141.8mph @3740lbs on 275's

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#2461665 - 03/05/18 06:07 PM Re: What rearend for turbo car? [Re: TRENDZ]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 30807
Loc: Bend,OR USA
Me thinks your confusing the Dana 60-2(they have the 60-2 cast into the housing above the pinion shaft scope) 4x4 front ends with the Dana 70, some of the later 3500 CTD trucks came with some version of Dana 70 up front and Dana 80 in the back shruggy
I'm going to do some research on those 61 carriers to see if they will accept the Dana 60 35 spline clutch type posi internals luck
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2461669 - 03/05/18 06:11 PM Re: What rearend for turbo car? [Re: Cab_Burge]
pittsburghracer Offline
Slowride

Registered: 02/02/05
Posts: 12838
Loc: PA.
Is Dana really Mopar or are you confused. Lmao.
_________________________
1970 Duster
Edelbrock headed 408
6.143@110.89 mph
9.73@135.05 mph shifting at 6700 RPM
422 Indy headed small block
6.001@113.27mph
9.44@138.23

Untitled by John Cadamore, on Flickr





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#2461672 - 03/05/18 06:16 PM Re: What rearend for turbo car? [Re: pittsburghracer]
pittsburghracer Offline
Slowride

Registered: 02/02/05
Posts: 12838
Loc: PA.
_________________________
1970 Duster
Edelbrock headed 408
6.143@110.89 mph
9.73@135.05 mph shifting at 6700 RPM
422 Indy headed small block
6.001@113.27mph
9.44@138.23

Untitled by John Cadamore, on Flickr





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#2461675 - 03/05/18 06:20 PM Re: What rearend for turbo car? [Re: moparmafia]
TRENDZ Offline
top fuel

Registered: 01/24/05
Posts: 1651
Loc: Milwaukee WI
Yes. Do some research.
As previously stated, all pre overdrive CTD trucks had 70U/71 rear axles. The only exception is the very rare 4:XX to 5:13 dana 70 in military lot tugs.
_________________________
"use it 'till it breaks, replace as needed"

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#2461681 - 03/05/18 06:29 PM Re: What rearend for turbo car? [Re: moparmafia]
6pakdakota Offline
member

Registered: 10/17/10
Posts: 78
Loc: michigan
The Dana 61 rear did come in ford trucks with a 3.07 gear, and a series 3 Dana 60 differential should work in it. That way you can run a spool in the Dana 61 as long as you use Dana 61 gears.

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#2461682 - 03/05/18 06:30 PM Re: What rearend for turbo car? [Re: pittsburghracer]
Cab_Burge Offline
I Win

Registered: 08/23/03
Posts: 30807
Loc: Bend,OR USA
Originally Posted By pittsburghracer
Is Dana really Mopar or are you confused. Lmao.
Touche, Essay grin stirthepot
You be right Bro up , Dana makes all of their parts for who ever wants to buy enough of them to warrant dealing with those companies.
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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