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Re: Rear End Strength [Re: 70charger512] #2553168
09/22/18 07:14 AM
09/22/18 07:14 AM
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Balt. Md
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383man Offline
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I have been running my 8-3/4 in my 63 since 2006 and its still holding up. But my car is 99% a street car as I only race it about once a year. Its all stock with a Detroit Locker and 4.30's. Ron

Re: Rear End Strength [Re: 70charger512] #2553174
09/22/18 09:06 AM
09/22/18 09:06 AM
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usa
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lewtot184 Offline
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I think the real issue is the inner pinion bearing. the 742 has a larger bearing and a 489 is even larger. these are Timken bearings that control the thrust on the pinion. the larger bearing will have more control and less deflection. there is a reason why any engine, 361 or larger, came from the factory with the larger pinion. in my opinion a 500cuin engine with a clutch with a dana 60 is the only solution for trouble free driving/racing.

Re: Rear End Strength [Re: 70charger512] #2553201
09/22/18 12:14 PM
09/22/18 12:14 PM
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Several people have mentioned That a back brace is a waste of time. Not exactly. It will not help ring and pinion life. It's real purpose on both 8 3/4 and 9" rears is to brace the housing so that it won't tow in and bend. Good power and dead hook can/will bend them.


In theory, there is no difference between theory and practice. In practice, there is.
Re: Rear End Strength [Re: 70charger512] #2553208
09/22/18 12:34 PM
09/22/18 12:34 PM
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Spokane Washington
ScottSmith_Harms Offline
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Quote:
Not all 4 speed Gen II Hemi cars used a Dana


All GenII Street & Race Hemi cars did (1966-71) seems like they might have learned something after introducing the Hemi in 1964/65 Race hemis.

Re: Rear End Strength [Re: 70charger512] #2553219
09/22/18 01:11 PM
09/22/18 01:11 PM
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Posts: 293
Spanaway, Washington State
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patosmith Offline
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Originally Posted By Nick Stevanovski
Since everyone loves dana 60’s so much, has anyone bought a complete dana 60 (or 8 3/4 if that option is still open to some) from moser engineering?

I have a 72 Challenger with a big block stroked to 505.
The car will see the strip a couple of times a year.
I bought a Moser dana 60 and I am very happy with it.

Re: Rear End Strength [Re: ScottSmith_Harms] #2553220
09/22/18 01:15 PM
09/22/18 01:15 PM
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Supercuda Offline
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Originally Posted By ScottSmith_Harms
Quote:
Not all 4 speed Gen II Hemi cars used a Dana


All GenII Street & Race Hemi cars did (1966-71) seems like they might have learned something after introducing the Hemi in 1964/65 Race hemis.


try quoting my whole post, I said what you did before your edit.

For the record

Originally Posted By Supercuda


All? Hmm wonder what they put in Hemi cars before they started using the Dana?

Wonder why they started using the Dana?

Not all 4 speed Gen II Hemi cars used a Dana.

But the point is, the 8 3/4 was failing in that application nd Chrysler went with the Dana.



They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Rear End Strength [Re: CSK] #2553234
09/22/18 01:40 PM
09/22/18 01:40 PM
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Chilliwack B.C. Canada
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RUNCHARGER Offline
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You're running a 550HP stick. I don't know why everyone thinks they are smarter than the thousands that have went before them and want to run an 8 3/4 or for that matter a stock 9 inch.
Spend a few thousand on your 8 3/4 beefing it up and changing the gear in it. Then when it breaks spend the $2k on a Dana 60 (better off an S60).
I just don't get why guys fight this after all these years.
What is the love for the 8 3/4?


Sheldon
Re: Rear End Strength [Re: RUNCHARGER] #2553249
09/22/18 02:27 PM
09/22/18 02:27 PM
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Posts: 1,134
Lost in Time
Iowan Offline
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Lost in Time
Originally Posted By RUNCHARGER
You're running a 550HP stick. I don't know why everyone thinks they are smarter than the thousands that have went before them and want to run an 8 3/4 or for that matter a stock 9 inch.
Spend a few thousand on your 8 3/4 beefing it up and changing the gear in it. Then when it breaks spend the $2k on a Dana 60 (better off an S60).
I just don't get why guys fight this after all these years.
What is the love for the 8 3/4?



Most race cars are nickel and dimed together and then the same for performance, if everyone that started out with 400 hp and didn't add a spool or limited slip to there 8 3/4 but jumped into a Dana instead. So if and when more power came along they would be bucks ahead?
Looking back that would have worked for me but some guys will run the same combination for thirty years and some are always looking for more. It's usually one motor combination that puts you over the practicality of the 8 3/4. It's never one part, drive shaft, might be time to look for room for more tire, better suspension, it's a never ending spiral of costs.
I know only a few racers that dont run on a very limited budget. So its nickel and dimed together and cry when it breaks.

As an edit: it has gotten easy to make power over the last twenty years, easy to overpower your chassis combination.


Have a great day
Iowan

"obsolete is neat"

Re: Rear End Strength [Re: Iowan] #2553253
09/22/18 02:43 PM
09/22/18 02:43 PM
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Chilliwack B.C. Canada
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Yes: I think that's the deal alright. If the OP said he had a 425HP 440 and an automatic I can see adding a good sure grip and set of gears. However he is running 550HP right away and changing to a manual trans. So please save $$$ and go directly to a Dana 60 and a good driveshaft.


Sheldon
Re: Rear End Strength [Re: 70charger512] #2553256
09/22/18 03:00 PM
09/22/18 03:00 PM
Joined: May 2015
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Lost in Time
Iowan Offline
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He's got to break it a few times before he learns.


Have a great day
Iowan

"obsolete is neat"

Re: Rear End Strength [Re: jcc] #2553307
09/22/18 06:15 PM
09/22/18 06:15 PM
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Posts: 25,618
Rio Linda, CA
John_Kunkel Offline
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Originally Posted By jcc
It has yet to be proven what exactly could be deflecting with a 8.75. I am not convinced the ring is not also a contributor here.


I agree, deflection of both undoubtedly contributes to gear tooth failure and the avalanche that follows. I believe that, under severe stress, the carrier bearing preload disappears and allows the ring gear to be deflected enough to lose the contact patch.


The INTERNET, the MISinformation superhighway
Re: Rear End Strength [Re: John_Kunkel] #2553311
09/22/18 06:24 PM
09/22/18 06:24 PM
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Supercuda Offline
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Originally Posted By John_Kunkel
Originally Posted By jcc
It has yet to be proven what exactly could be deflecting with a 8.75. I am not convinced the ring is not also a contributor here.


I agree, deflection of both undoubtedly contributes to gear tooth failure and the avalanche that follows. I believe that, under severe stress, the carrier bearing preload disappears and allows the ring gear to be deflected enough to lose the contact patch.


Does it matter what is deflecting? Once either or both deflect it is all over.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Rear End Strength [Re: Supercuda] #2553335
09/22/18 07:28 PM
09/22/18 07:28 PM
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Rio Linda, CA
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Well, I'm thinking of the "straw that broke the camel's back" analogy, one part deflecting might not be as bad as the combination of two parts deflecting.

As far as being "all over" with any deflection, it's a matter of degree.


The INTERNET, the MISinformation superhighway
Re: Rear End Strength [Re: 70charger512] #2553497
09/23/18 04:04 AM
09/23/18 04:04 AM
Joined: Jan 2003
Posts: 27,421
Balt. Md
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383man Offline
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I forgot to add my car is an auto car. I agree with everyone that if my car was a stick car no way would I race it with the 8-3/4. I don't race on the street so the only time I race it and launch it hard on sticky tires is maybe a few passes a year. I still want to go to a Dana as I know I am pressing my luck when I race it but funds just wont let me right now. Ron

Re: Rear End Strength [Re: 383man] #2553560
09/23/18 11:27 AM
09/23/18 11:27 AM
Joined: Sep 2003
Posts: 19,243
north of coder
moparx Online content
"Butt Crack Bob"
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i missed the part about converting to a stick ! blush as the saying goes : "my bad !" anyone got some good eyeballs they can donate ? biggrin
beer

Re: Rear End Strength [Re: 70charger512] #2553561
09/23/18 11:33 AM
09/23/18 11:33 AM
Joined: Jan 2003
Posts: 13,319
Marion, South Carolina [><]
an8sec70cuda Offline
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Marion, South Carolina [><]
Originally Posted By Nick Stevanovski
Since everyone loves dana 60’s so much, has anyone bought a complete dana 60 (or 8 3/4 if that option is still open to some) from moser engineering?


Like said before, if the car never hooks you'll likely never break the 8.75. If it hooks at all, it won't last long. Your power w/ a manual trans WILL kill an 8.75...not if, but when.

I have a Moser 60 in my cuda that I bought in either 2003 or 2004. No complaints, but if I had to do it over again, I'd get a Strange S60. The only reason is the Strange unit has side adjusters for setting the backlash which is much easier to work with.

I have 2 road runners that I used truck Dana 60 rears and cut them down to fit. Work great and a lot cheaper if you don't mind the extra work.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Rear End Strength [Re: GomangoCuda] #2553562
09/23/18 11:35 AM
09/23/18 11:35 AM
Joined: Jan 2003
Posts: 13,319
Marion, South Carolina [><]
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Marion, South Carolina [><]
Originally Posted By GomangoCuda
Several people have mentioned That a back brace is a waste of time. Not exactly. It will not help ring and pinion life. It's real purpose on both 8 3/4 and 9" rears is to brace the housing so that it won't tow in and bend. Good power and dead hook can/will bend them.


By the time you start bending the 8.75 housing, you've already been breaking ring and pinions. For the money it costs to bandaid an 8.75, you could have built a Dana for it and forgotten about it.


CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
Re: Rear End Strength [Re: 70charger512] #2553658
09/23/18 02:52 PM
09/23/18 02:52 PM
Joined: Jan 2004
Posts: 8,193
fredericksburg,va
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cudaman1969 Offline
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Since you're going to use a clutch, there is a gizmo out witch is called the door closer. It fits on the clutch rod to slow down engagement just enough to reduce breakage of componites. Wish I had the manufacturs name, but look it up on line. I will use it on my car when done.
If you dead hook with an 8-3/4, you'll be picking parts off the ground, stay away from the radials.
My 64 (auto) broke all the ring gear teeth off after 10 passes, had ladder bars, spool, strange axels and 14-32 slicks, 842 case. Out it came and Dana back in reusing the axels.

Re: Rear End Strength [Re: cudaman1969] #2553662
09/23/18 03:14 PM
09/23/18 03:14 PM
Joined: May 2012
Posts: 1,812
South Bend
John Brown Offline
top fuel
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South Bend
Originally Posted By cudaman1969
Since you're going to use a clutch, there is a gizmo out witch is called the door closer. It fits on the clutch rod to slow down engagement just enough to reduce breakage of componites. Wish I had the manufacturs name, but look it up on line. I will use it on my car when done.


Clutchtamer?


July 19th should be "Drive Like Rockford Day". R.I.P. Jimmie.
Re: Rear End Strength [Re: 70charger512] #2553663
09/23/18 03:17 PM
09/23/18 03:17 PM
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Porter67 Offline
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I have not worried about any rear diff issues in nearly 10 year.

Ya know why? Because I bought two S60-s after reading and seeing all the "like" junk posted here and having a stock 440-6 auto car shred a 8 3/4

Now in these times, used 8 3/4 prices have gotten really stupid to the point some are within a few hundred bucks of a basic S60.

Overbuild a dam and you will never get your feet wet.

Sorry but my opinion is spending money on a 8 3/4 these days is like tossing money in the trash with a healthy stroker build and some serious driving.

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