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  #1  
Old 02-12-2006, 06:39 PM
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rallye72 rallye72 is offline
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8 1/4, how much abuse can it take?

If I used an 8 1/4 replaced the carrier with a spool , richmond gears(around 4.56) new bearings, and moser axle shafts. Where would my weak point be then? would it hold up to low 11 second passes in a 3000 lbs vehicle with slicks?
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  #2  
Old 02-12-2006, 06:50 PM
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Biggrin

Yes, it will take it. A 1/4 will take just as much abuse as the 8 3/4 will. After all it was the 3/4's replacement since the 3/4 has so much flex from the axle housings. Is this for the truck??
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Old 02-13-2006, 01:23 AM
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I think it would hold up for a while. I think low 11's would be pushing it.

I would only do it as an interm measure, personally.

Have you measured the weight at 3000 pounds or is that an estimate?

That will be key. If the real weight is closer to 3600 pounds and the car running low 11's on a real life dragstrip (instead of an internet one...LOL) you WILL destroy that diff in short order.
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Old 02-13-2006, 05:33 AM
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You've replaced all of the weak points of the 8¼".

Which yoke are you using? I would go with the u-bolt design and then replace the u-bolts with caps
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  #5  
Old 02-13-2006, 11:44 PM
mgreen2994 mgreen2994 is offline
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Default 8 1/4

where do you find a spool for a 8 1/4 ???
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  #6  
Old 02-14-2006, 10:51 AM
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Biggrin

I'd check Randy's for starters. www.ringpinion.com
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  #7  
Old 02-14-2006, 08:25 PM
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Quote:
Originally Posted by ehostler
You've replaced all of the weak points of the 8¼".

Which yoke are you using?
Whast yokes are out there for the 8-1/4 and whats the weak points
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  #8  
Old 02-14-2006, 08:52 PM
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Hey DW, he wants a spool, not a starter, but that place might have em any ways.


J/K
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  #9  
Old 02-14-2006, 09:19 PM
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Quote:
Originally Posted by rumblefish360
Whast yokes are out there for the 8-1/4 and whats the weak points?
7260 with straps
7260 with u-bolts
7290 with straps
7290 with u-bolts

The 7290 is a larger/stronger U-joint.
The U-bolt is stronger than the straps.
The aftermarket caps are stronger than u-bolts (the caps replace the u-bolts on the u-bolt design yoke).

Once you've done all of that, the weak point becomes the pinion.
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  #10  
Old 02-14-2006, 10:34 PM
mgreen2994 mgreen2994 is offline
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Default 8 1/4

like was asking, where do you find a spool for a 8 1/4 ?? All ring&pinon has is 8 3/4s
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  #11  
Old 02-15-2006, 12:40 AM
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Beefed up parts for an 8 1/4 can't be cheap given thier relative lack of popularity.

Wouldn't it make more sense to build a dana or an 8 3/4? There is a guy on Moparts who can build you a complete dana for 1200 bucks.

Look for him there. login Doctor Diff

I have an email addy for him anyone can pm me for.
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Old 02-15-2006, 09:32 AM
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Quote:
Originally Posted by dave571
Beefed up parts for an 8 1/4 can't be cheap given thier relative lack of popularity.

Wouldn't it make more sense to build a dana or an 8 3/4? There is a guy on Moparts who can build you a complete dana for 1200 bucks.
I would venture a guess that Chrysler has put 2 to 3 times as many 8 1/4's under vehicles as 8 3/4's. They are still being used today in trucks and Jeeps. There is no lack of parts for the 8 1/4" and they are quite often cheaper than the parts for an 8 3/4.

No arguing that an 8 3/4 or dana 60 is a stronger rear end but if you have the 8 1/4 it can be built to take a lot of abuse without much investment.

One thing no one has mentioned that is usually always mentioned when beefing up the 8 1/4" is a reinforced cover. They keep the main case from flexing and have jack screws that support the bearing caps.
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  #13  
Old 02-15-2006, 02:28 PM
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BS!

Quote:
Originally Posted by dgc333
I would venture a guess that Chrysler has put 2 to 3 times as many 8 1/4's under vehicles as 8 3/4's. They are still being used today in trucks and Jeeps. There is no lack of parts for the 8 1/4" and they are quite often cheaper than the parts for an 8 3/4.

No arguing that an 8 3/4 or dana 60 is a stronger rear end but if you have the 8 1/4 it can be built to take a lot of abuse without much investment.

One thing no one has mentioned that is usually always mentioned when beefing up the 8 1/4" is a reinforced cover. They keep the main case from flexing and have jack screws that support the bearing caps.
I doubt that 2-3 times guess would be accurate given the years the 8 3/4 was produced, vs the years the 8 1/4 was produced, BUT let's say you are right.

How many do you see with spools and good sfi aftermarket axles vs an 8 3/4?

stock parts for an 8 1/4 may be more prevelant, but not performance ones.
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  #14  
Old 02-18-2006, 10:53 AM
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The 8 3/4 was produced from 57 to 74 (17 yrs) the 8 1/4 started in 73 and is still being produced (33 years and counting) so 2-3 times is a resonsable guess.

Detroit, Auburn, Eaton, Moser, Strange can all supply parts for the 8 1/4" for equivalent prices to the 8 3/4. If you want the most axle for the least amount of money go with a Ford 9".

The point I have been trying to make is if you have an 8 1/4 axle and you are building a car with 500 Hp or less there is no reason not to use it.
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  #15  
Old 02-18-2006, 12:35 PM
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Well, I'm probably going to look for a pre 71 B-body 8 3/4 and build it up. I'm trying to beef up my dakota and as of now will be running a small block with a 150 shot of spray. If I stick with an 8 3/4 then I will still have interchangeability with my challenger,dart,and duster in case I destroy the dakota or want to quit racing. Thanks
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  #16  
Old 02-19-2006, 01:24 AM
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Biggrin

Quote:
Originally Posted by rallye72
Well, I'm probably going to look for a pre 71 B-body 8 3/4 and build it up. I'm trying to beef up my dakota and as of now will be running a small block with a 150 shot of spray. If I stick with an 8 3/4 then I will still have interchangeability with my challenger,dart,and duster in case I destroy the dakota or want to quit racing. Thanks
There's a couple truck 3/4's for sale on this site if you have not noticed them. They might work for ya.
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