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  #1  
Old 04-11-2002, 11:49 PM
Head Crash Head Crash is offline
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Unhappy Rear casing

Haven't been on the board for quite a while now and need to ask a question that has probably been asked a gazillion times before....

What would be the best case for a low 11 second b body, auto, weighs in at 3600 lbs with driver. I currently am running a 742 with 4.10's but half my buddies are saying go with the 489 and the other half are saying the 742 is the better.

Any help appreciated....
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  #2  
Old 04-12-2002, 12:35 PM
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3bolt main 3bolt main is offline
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need the answer to this 1 myself i know its got to do with some thinga ma bob i dont really have grasp of yet ok fellas a little help please
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Old 04-12-2002, 01:46 PM
John Kunkel John Kunkel is offline
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There's very little agreement on this subject. The 489, with its larger pinion stem, offers the highest gear strength but the pinion bearings have about 15% less load capacity than the 742.
The crush sleeve in the 489 is often considered a weakness but it can be eliminated with an aftermarket kit.
So, each has its plusses and minuses and it's up to the individual to decide.
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Old 04-12-2002, 02:18 PM
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dusterbd dusterbd is offline
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head crash: if youre not having problems with the current setup, why worry? on the other hand, if youre going to make it considerably faster, you may consider going to a dana. nothing can hurt em...
its been my experience that with all the different casings, if given enough abuse and not enough attention, theyll break. although its kinda neat when they do, its expensive.
mike
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Old 04-12-2002, 02:51 PM
Jims451 Jims451 is offline
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For the most part they are about the same. If you use the 489 case, get the spacer kit to eliminate the crush sleeve. They should both hold nearly the same power. I think ARP sells bolts for the bearing half shells, and welding a back brace on the housing may reduce some flex. If you break that, then get a Dana 60
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Old 04-12-2002, 07:56 PM
Doug Wilson Doug Wilson is offline
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My case is a 741. Anyone have any comments on it?
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Old 04-12-2002, 09:09 PM
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3bolt main 3bolt main is offline
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Quote:
My case is a 741. Anyone have any comments on it
it's old ...and probably smells funny LOL
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Old 04-13-2002, 01:06 AM
Doug Wilson Doug Wilson is offline
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Thanks... I needed that.
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Old 04-13-2002, 09:35 AM
Jims451 Jims451 is offline
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I have been running a used set of 3.91:1 gears in a 741 case in the Charger, so far no problems, but you have to realize that I don't launch the car really hard due to traction problems, usually mid to upper 1.8 second 60' times for my #4,150 Charger (with driver.)
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Old 04-13-2002, 12:21 PM
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3bolt main 3bolt main is offline
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Sorry about that Doug , couldnt resist i think parts are a little harder to get for a 741
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  #11  
Old 04-13-2002, 02:01 PM
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dusterbd dusterbd is offline
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the 741 in the duster has held up well for 193,000 miles. and, at leas 20,00 of those have been with me never taking my foot from flat on the floor. if it can hold up to the burnouts, powershifting, mileage, and general lack of attention (fluid hadnt been changed in so long i had a hard time finding all the rearend nuts under the grease buildup), and still be qualified as the weakest one, ill take my chances and say that the 489 would hold up to a nuclear war.
mike
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