Moparts

How fast with a stock 8 3/4

Posted By: MrSixpack

How fast with a stock 8 3/4 - 03/16/14 07:09 PM

How fast have you been with a stock 8 3/4.
60 feet and et.
Weight/Hp/tire size

Just want to know when I will break my 8 3/4
Looking for a 9" or Dana,but they are hard to find here.
I wonder if my 68 B-body Dana will fit my 1980 F-body that has stock frame rail and no modifications to the wheel wells.
I will run 275 Micky T's drag radial.

Let the bashing begin
Posted By: MR_P_BODY

Re: How fast with a stock 8 3/4 - 03/16/14 07:21 PM

I will assume you will back brace it... I was running
mid 9s with a totally stock center... had just over
600 passes on it when the cap broke.. thats when I
changed over to a alum center... on the stock one
I was 2400# with 620 hp, 1.23 60', 13.5 X 31 slicks..
if you were to put load bolts on the back to touch
the caps it helps alot
Posted By: one bad fish

Re: How fast with a stock 8 3/4 - 03/16/14 07:28 PM

they last pretty well
Posted By: 1974 474 Duster

Re: How fast with a stock 8 3/4 - 03/16/14 08:47 PM

Mine made it into the 10.20 range, but was 60'ing around 1.30 range. Car weighed 3200#. Then is started clearing ring gears on a regular basis. Went to a Dana 60 then. As for a 68 Dana in an F-body. The spring perches will be inward 1/2" on each side. You can put one side on the pin & bolt it in place. Then just use a strap to pull the other side in. Only 1" total difference. The spring will go in that amount no problem. Have put 2 68 8 3/4's in my F-bodies w/no problem's at all there. Lots of tire space w/right offset wheels
Thanks, Ken
Posted By: MrSixpack

Re: How fast with a stock 8 3/4 - 03/16/14 09:03 PM

Yes it is back braced, but still original axels and pumpkin with a 3.91 gear and clutch type limited slip.

It will be exciting to see how it will work, I think twisting the axels are what will happen first.

Thanks
Posted By: 383man

Re: How fast with a stock 8 3/4 - 03/16/14 09:08 PM

I have run 10.70's at 3700 lbs with an all stock 8-3/4. I know I am pushing my luck and want to go with a Dana some time when I can afford it. I use a Dynamic 9.5 street/strip converter as my car does not launch real hard but hard enough for me which I am glad as it does not seem to be to hard on the rear. But I only race a few times a year. Ron
Posted By: Mr.Yuck

Re: How fast with a stock 8 3/4 - 03/16/14 10:23 PM

Depends on the weight.. a backbraced 8.75 should be good into the 10's. I replace the axles in mine after people told me they are no good under 12.0 however they looked fine when removed. I want to back brace mine before I hit it w/ a 150 shot.
Posted By: 71yelladustr

Re: How fast with a stock 8 3/4 - 03/16/14 11:27 PM

My experience is, 12 sec heavy car + 4 spd + 440 + slicks = broken 8 3/4. The ring and pinion will trashed. Never had any axle issues though. Keeping the weight down and driveline shock (no 6500 rpm clutch drops) will be the key to making an 8 3/4 live.
Posted By: dizuster

Re: How fast with a stock 8 3/4 - 03/16/14 11:42 PM

My 100% stock 8 3/4 went best of 1.50 60ft in a 3700lb car.

I took the axles out and they were all twisted up.


Also, I tried (well accidentally tried) to leave REAL hard on it the last time out.

Sheared the pinion off, but the stock axles survived.


IMG_20130823_200437_896-1 by wright2305, on Flickr
Posted By: StealthWedge67

Re: How fast with a stock 8 3/4 - 03/17/14 12:37 AM

My experience was the differential itself broke, side gears sheared. Mine now is backbraced and has a locker in it with Dr.Diff axles. So far so good.
Posted By: Anonymous

Re: How fast with a stock 8 3/4 - 03/17/14 01:25 AM

9.98 @ 139. No back bracing.

Attached picture 8076793-dudekrr.png
Posted By: shakerjoe

Re: How fast with a stock 8 3/4 - 03/17/14 01:42 AM

Posted By: 383man

Re: How fast with a stock 8 3/4 - 03/17/14 01:45 AM

Quote:

My 100% stock 8 3/4 went best of 1.50 60ft in a 3700lb car.

I took the axles out and they were all twisted up.


Also, I tried (well accidentally tried) to leave REAL hard on it the last time out.

Sheared the pinion off, but the stock axles survived.


IMG_20130823_200437_896-1 by wright2305, on Flickr



That makes me nervous. My best 60 is a 1.50 as I average from 1.50 to 1.53. I forgot I do have a Detroit Locker in my 8-3/4 but all the rest is stock including the axles.
I will say I broke parts in an 8-3/4 with an 11.90 Dart that was a 340 with a 4-speed and I did launch it hard. I would tach it up to about 5500 and then floor it as I let the clutch out and it broke a ring and pinion and a few U-joints and twisted a driveshaft. My sons Dart has run 11.40's with a stock 8-3/4 with a 727 and neither his Dart or my 63 have broke our 8-3/4's even though both are alot faster then my old 4-speed Dart. But both our cars are auto's which are alot easier on the drivetrain. Ron
Posted By: mopar65

Re: How fast with a stock 8 3/4 - 03/17/14 02:49 AM

I have a back braced 8-3/4 in my 3500 pound big block 73 dart. its got moser 30 spline axles/ spool and 4.30 Richmond gears.which after about 20 some passes has been holding up fine. with the 4.30 the car has been a best of 10.49 in the 1/4 and a 60 foot of 1.48.
now when i first put the 440 in my dart i only got to make 4 passes till the Richmond 4.10 gears went boom. i ran a 10.66 in the 1/4 but only a 1.56 60 foot. when ever i get enough money saved up i will be putting a Dana in my 73 duster. here is a pic of the 4.10 gears. thanks Mopar65

Attached picture 8076935-005[1280x768].JPG
Posted By: actionange

Re: How fast with a stock 8 3/4 - 03/17/14 03:18 AM

Back braced housing, Mark Williams spool and 35 spline axles. 742 case.
Richmond 3.91 gears.
Leave the line at 2000 rpm.
Runs a 10 teens, 10 twenties.
Race weight is 3750 lbs.
Still going.
Where's Quicktree? LOL..
Posted By: onefastindy

Re: How fast with a stock 8 3/4 - 03/17/14 04:59 AM

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.

Attached picture 8077192-image.jpg
Posted By: Thumperdart

Re: How fast with a stock 8 3/4 - 03/17/14 05:38 AM

Quote:

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.



Tell us more.................
Posted By: racerx

Re: How fast with a stock 8 3/4 - 03/17/14 05:24 PM

Quote:

Quote:

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.



Tell us more.................

^^^What he ask^^^
Posted By: Quicktree

Re: How fast with a stock 8 3/4 - 03/17/14 05:30 PM

Quote:

Back braced housing, Mark Williams spool and 35 spline axles. 742 case.
Richmond 3.91 gears.
Leave the line at 2000 rpm.
Runs a 10 teens, 10 twenties.
Race weight is 3750 lbs.
Still going.
Where's Quicktree? LOL..

I can tell you he's not wasting money on an 8/3/4 thats for sure
Posted By: Polarapete

Re: How fast with a stock 8 3/4 - 03/17/14 05:53 PM

It is relatively easy to build a Dana 60, because all you have to do is to narrow the axle tubes to fit your application, and they are straight, no curves. Moser, Strange and others have the housing ends you need. You just have to decide what brakes to use. I built the latest one from a Jeep J20 rear axle that was 40 years old. It came from a wrecking yard with a 4.10 gear on a PowerLock carrier with 35 spline axles and tapered Timken bearings, 12" drum brakes, 5 on 5.5" bolt pattern that will easily fit my '87 D100. The Dana had been rebuilt (new bearings, clutches & brakes) when I got it for $400.00. I put another $400.00 into it having 1 tube shortened and 1 axle shortened and resplined. Your experience may differ, but I am pleased
Posted By: dragram440

Re: How fast with a stock 8 3/4 - 03/17/14 06:00 PM

8 3/4's are super strong and I wouldn't worry about it. I would recomend axles, gears and spool, back brace wouldn't hurt either.
Posted By: onefastindy

Re: How fast with a stock 8 3/4 - 03/17/14 06:20 PM

440 with 440-1's and 150 shot.
Posted By: roadhazard

Re: How fast with a stock 8 3/4 - 03/17/14 06:28 PM

Quote:

440 with 440-1's and 150 shot.




How many passes on it and at what weight. Also do you use a trans brake?
Posted By: onefastindy

Re: How fast with a stock 8 3/4 - 03/17/14 07:22 PM

Car weighs 3260. It's a foot brake car. Stock stuff lasted about 25 passes with that 440. In that pic it had a 1.29 60 ft.
Posted By: Paul_Fancsali

Re: How fast with a stock 8 3/4 - 03/17/14 10:30 PM

The worst I broke on a 8.75 is a carrier bearing that turned into a metal paste. I now use BCA when I can Broke with a 340 4spd and 9inch slicks car ran like crazy until it locked up
Posted By: bdaz smblk

Re: How fast with a stock 8 3/4 - 03/18/14 01:14 AM

Quote:

Quote:

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.



Tell us more.................

Thumper are u trying to stir the pot?lol
Posted By: Thumperdart

Re: How fast with a stock 8 3/4 - 03/18/14 01:39 AM

Quote:

Quote:

Quote:

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.



Tell us more.................

Thumper are u trying to stir the pot?lol



No sir, I just trip on the fact that some 11-12 second cars kill em and these guy`s and myself run 9`s and faster and they live.........But as Quick pointed out, guess I`m not totally hookin.............
Posted By: racerx

Re: How fast with a stock 8 3/4 - 03/18/14 03:19 AM

Quote:

Car weighs 3260. It's a foot brake car. Stock stuff lasted about 25 passes with that 440. In that pic it had a 1.29 60 ft.

Footbreaken a 3200 lb.car witha 1.29 60's is hookin
Posted By: racerx

Re: How fast with a stock 8 3/4 - 03/18/14 03:27 AM

Quote:

Quote:

Quote:

Quote:

I've been 5.80's in the 1/8 with 1.29 60ft with stock axles and sure grip before it twisted the housing. Now it's got a new one that's back braced with moser axles and spool with billet caps.



Tell us more.................

Thumper are u trying to stir the pot?lol



No sir, I just trip on the fact that some 11-12 second cars kill em and these guy`s and myself run 9`s and faster and they live.........But as Quick pointed out, guess I`m not totally hooking.............

Thump. doesn't your car has the MW cap on it?I think the op.was referring to a stock rear.With that said,i think that the reason so many 8.75's or in the 9's,8's along with other modification that they do to these rearends
Posted By: Thumperdart

Re: How fast with a stock 8 3/4 - 03/18/14 03:30 AM

Quote:

Quote:

Car weighs 3260. It's a foot brake car. Stock stuff lasted about 25 passes with that 440. In that pic it had a 1.29 60 ft.

Footbreaken a 3200 lb.car witha 1.29 60's is hookin




I dream of those #`s.............
Posted By: onefastindy

Re: How fast with a stock 8 3/4 - 03/18/14 05:15 AM

Thanks.. I've spent a lot of time and money to make it work right. I've only ran it in 1/4 mile a few times. It went low 9's and still footbraking. Now it's time to pass it on to somebody else.
Posted By: Thumperdart

Re: How fast with a stock 8 3/4 - 03/18/14 06:43 AM

I`ll take it..................Thankxxx...........
Posted By: onefastindy

Re: How fast with a stock 8 3/4 - 03/18/14 04:09 PM

It's on here for sale. I'm sure it would look good on the west coast...
Posted By: FastmOp

Re: How fast with a stock 8 3/4 - 03/19/14 02:27 AM

Hi 6's in the 1/8. Anything past 6.80 is gambling on stock everything.
I went 6.00 with my 8&3/4. But the trans break is the week link finder.
Posted By: MR_P_BODY

Re: How fast with a stock 8 3/4 - 03/19/14 02:54 AM

Quote:

Hi 6's in the 1/8. Anything past 6.80 is gambling on stock everything.
I went 6.00 with my 8&3/4. But the trans break is the week link finder.



I've been using a trans brake from day one.. like I
said I got over 600 passes on a stock center.. even
with the cone style posi.. all with the trans brake
but my car is lite... each pass was from 5200 rpm
or up launches...weight tends to kill them
Posted By: dogdays

Re: How fast with a stock 8 3/4 - 03/19/14 03:13 AM

To the OP:

The best place for you to find a Dana 60 in Sweden might be a scrapyard that specializes in US Military vehicles. I'm thinking Germany.

The Dana 60 is a 3/4 ton truck rear end, it was never meant to go under a car. But it was in the parts chain when Mopar engineers decided they needed something stronger than an 8 3/4.

In a 3/4 ton or even a 1-ton vehicle the rear will have full floating 8 lug hubs. The idea is to cut the axle ends off and weld on new ends like 8 3/4 ends so you can use your existing brakes. Then you buy custom axles.

Doctor Diff would be the guy I'd talk to, he would be the most helpful, in my opinion. He could walk you through the steps and help you get the right length axles.

Most all Dana 60s in military vehicles will have 4.10 or numerically higher gears and limited slip differentials.

Good Luck!

R.
Posted By: 70dusterjohn

Re: How fast with a stock 8 3/4 - 03/19/14 03:32 AM

We ran 9.80s all day long with a stock 8 3/4 ! And I do mean stock ! My best 60ft was 1.29 with it, we were close to 3500lbs race ready ! I did that for a year, then put a spool back brace axles in it, then ran it for another year and switched to the strange 60 from doc diff ! Car went just as quick until I broke the block
Posted By: an8sec70cuda

Re: How fast with a stock 8 3/4 - 03/19/14 02:25 PM

I broke something in the stock sure-grip running 11.40s at 3700#. Found twisted axle splines when I took it apart.
Changed to a spool w/ 35 spline axles and all was good until I started running mid 10s at the same 3700#. It took the teeth off the ring and pinion. Car never 60 footed all that well (1.49-1.51) w/ a best of 10.40 at 129 mph.
Once that happened I put a Dana in it. That was in 2003...haven't touched it since.
Posted By: racerx

Re: How fast with a stock 8 3/4 - 03/19/14 02:51 PM

Wish i knew at what weight kills them as i broke one bout 20 years ago on the street.Tore it apart and it was the spider gears,Went to a spool 33 spline with the street/stripe axles broke an axle,upgraded to a 35 spline/race axles all was good ran with that setup for about 10 years never broke a gear or anything(wish we had a wood knocking icon )but went to a different gear(4.56 to 4.10)which kind of raising my worried factor cause the 4.10 ring gear seems a little thin we shall see.
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