Help me pick my rear-end!
#952024
03/16/11 03:18 PM
03/16/11 03:18 PM
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Joined: Aug 2009
Posts: 740
Anderson, IN
1969RR
OP
super stock
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OP
super stock
Joined: Aug 2009
Posts: 740
Anderson, IN
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No, the one in my Challenger! I have a '70 Challenger RT, 500ci, Mopar 509 cam, Indy EZ heads, 6 PAK, 4 speed. What I have now is the stock 741. Numbers on case are: 2070741 26A 3.23 ratio tag. The car is in storage now, and I'm wanting to get a new, stronger, taller gear chunk. I'm sure what I have now is not strong enough for the new 500ci engine. What case can I use in this rear? What size yoke does this 741 use? And, what will interchange? Where would the best place to buy a new or rebuilt unit be. Can I use the 489 or 742 section? Thanks in advance everyone! Jeff
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Re: Help me pick my rear-end!
[Re: Kern Dog]
#952026
03/16/11 03:26 PM
03/16/11 03:26 PM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
I Win
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I Win
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Quote:
I love the title of this post!
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Re: Help me pick my rear-end!
[Re: 1969RR]
#952028
03/16/11 03:32 PM
03/16/11 03:32 PM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
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I Win
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Quote:
Hello, I knew everyone would get a kick out of the title! I should have elaborated a bit more. I do want to drive the car to shows. I don't race, so slicks will never be on the car. I want to be able to drive 65-70 mph. I'm just not sure what to buy. I have to be concerned about yoke sizes correct? I'd go the Dana route if I could find one. It's just easier to sway the center section. Thanks again! Jeff
If this is the case the 741 will live a long and happy life in your application , what gear ratio do you want to switch to ?
A 741 could have either yoke size on it , all 3 cases are weakest in the same points , gear teeth and the yoke end of the pinion. If you aren't going to run slicks what you have is fine even for the occasional burnout .
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Re: Help me pick my rear-end!
[Re: 1969RR]
#952030
03/16/11 03:44 PM
03/16/11 03:44 PM
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Joined: Jan 2003
Posts: 5,138
East Aurora (Buffalo) NY
RoadRunner
master
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master
Joined: Jan 2003
Posts: 5,138
East Aurora (Buffalo) NY
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For what its worth, this is my recommendation:
If set on a 8-3/4, then I would find a 489 case with 3.55 gears. Maybe 3.23, but I think the 3.55 would be a nice jolt off the line without too much screaming on the highway. Frankly, driving my Road Runner around 60-65 mph is fine with me. I don't need to do 70mph.
If you could swing it, I would go with an after market Dana with 3.54.
68 Road Runner (383/4speed, post car w/decor pkg) - Major Project
69 Road Runner w/472 Hemi & 4 speed.
70 Challenger R/T SE EF8 w/ V9J, U - A32 - Major Project
2023 Ford Mach 1
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Re: Help me pick my rear-end!
[Re: 1969RR]
#952031
03/16/11 03:56 PM
03/16/11 03:56 PM
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Joined: Dec 2007
Posts: 18,157
Mass
DAYCLONA
I Live Here
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I Live Here
Joined: Dec 2007
Posts: 18,157
Mass
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IMHO, I wouldn't waste the time on the 8 3/4, with the engine/driveline combo you have, a DANA 60 will offer peace of mind when you decide to flog it,....several vendors offer DANA 60 set-ups, complete bolt-ins,...Dr Diff (Moparts member) to Strange Engineering, to DTS, etc,....contact DR Diff for a quote before you dump any money into the 8 3/4 pig 
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Re: Help me pick my rear-end!
[Re: DAYCLONA]
#952032
03/16/11 05:19 PM
03/16/11 05:19 PM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
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Quote:
IMHO, I wouldn't waste the time on the 8 3/4, with the engine/driveline combo you have, a DANA 60 will offer peace of mind when you decide to flog it,....several vendors offer DANA 60 set-ups, complete bolt-ins,...Dr Diff (Moparts member) to Strange Engineering, to DTS, etc,....contact DR Diff for a quote before you dump any money into the 8 3/4 pig
You can also contact dr. diff for a rebuilt chuck with a sure grip with the gear ratio you want, but I agree , you will probably end up hurting it anyway and the money you pay for the chuck will pay for at least half a dana 60 ready to bolt in .
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Re: Help me pick my rear-end!
[Re: JohnRR]
#952034
03/17/11 03:26 AM
03/17/11 03:26 AM
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Joined: Mar 2010
Posts: 357
Lake Elmo, MN
Evil Monkey
enthusiast
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enthusiast
Joined: Mar 2010
Posts: 357
Lake Elmo, MN
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Quote:
Quote:
IMHO, I wouldn't waste the time on the 8 3/4, with the engine/driveline combo you have, a DANA 60 will offer peace of mind when you decide to flog it,....several vendors offer DANA 60 set-ups, complete bolt-ins,...Dr Diff (Moparts member) to Strange Engineering, to DTS, etc,....contact DR Diff for a quote before you dump any money into the 8 3/4 pig
You can also contact dr. diff for a rebuilt chuck with a sure grip with the gear ratio you want, but I agree , you will probably end up hurting it anyway and the money you pay for the chuck will pay for at least half a dana 60 ready to bolt in .
That's exactly the way I looked at it when I broke a main cap in the 8 3/4 489 case in my Cuda. Buy another 8.75 chuck, and always have to wonder if it's going to break again? Or buy a Dana, and not have to worry about breaking it, but spend twice as much money? I was lucky that I had money to spend at the time, and I figured if I broke it once, it could break again, so I went with a Strange Dana. If you can afford it, the peace of mind is well worth it.
1974 'Cuda 360/TKO
1990 Ram Van
1998 Neon
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Re: Help me pick my rear-end!
[Re: Kern Dog]
#952037
03/17/11 10:35 AM
03/17/11 10:35 AM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
I Win
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I Win
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Quote:
I wonder what sort of havoc can result from a grenaded diff. I would hope that the axle flanges would keep them from flying out. I worry about outer body damage from that sort of thing because shiny paint can make a man paranoid.
The axles are retained by the bearings so the only way the wheel is going to come off is if you break lugs , break the axle outside of the flange or if the end of the housing breaks off. If you have an auto trans you can potentially damage the rear sprag if you are in low and the rear band is not applied .
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Re: Help me pick my rear-end!
[Re: Kern Dog]
#952039
03/17/11 04:09 PM
03/17/11 04:09 PM
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Joined: Jan 2003
Posts: 75,012
U.S.S.A.
JohnRR
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I Win
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Quote:
I can live with a $600-800 dollar trans going out. Having to repair twisted quarter panels could really bunk me out.
What you need to know is if you lose the driveshaft or blow the rear you MUST pull the trans and check the sprag.
Don't treat it like your 2X cam lobe eating fiasco because if you don't do it the front drum can EXPLODE and guess where it's going ....
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