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the limits of the 8.25

Posted: November 18th, 2008, 9:49 pm
by Shark
hey guys, ive been away for a while cause my hot rod project has been receiving more attention than my jeeps lately but i have a question that i thought you guys might be best to ask.

my Model A will be receiving a 460 ford big block and i was going to get a 9 inch rear to handle the power. however, im building this thing on a tight budget and i have an old chryco 8.25 sitting in the back yard.

how much power can that thing handle? should i give it a try? if i break an axle i can always get the 9 inch later. will it be dangerous?

thanx in advance.

Re: the limits of the 8.25

Posted: November 19th, 2008, 6:49 am
by yuppiexj
I personally would run the 8.25, if it's going to fail, it will snap a shaft or blow the spider gears.

Either way no parts will go flying out, it just won't go anymore.
Being a c clip axle you should get a rollback to take it home.

Re: the limits of the 8.25

Posted: November 19th, 2008, 8:20 am
by John
What year 8.25, pre 97 had smaller spline count, made the unit a little stronger than a Dana 35 after 97 with increase in count of the axle splines it is closer to the Dana 44 but a little weaker overall. If you have the newer, behind a 460 you might try it as you already have it at hand, I don't think I could advise you to use the older design behind a 460.
John

Re: the limits of the 8.25

Posted: November 19th, 2008, 8:22 am
by yuppiexj
John wrote:What year 8.25, pre 97 had smaller spline count, made the unit a little stronger than a Dana 35 after 97 with increase in count of the axle splines it is closer to the Dana 44 but a little weaker overall. If you have the newer, behind a 460 you might try it as you already have it at hand, I don't think I could advise you to use the older design behind a 460.
John
I forgot about the 27/29 spline change.

Re: the limits of the 8.25

Posted: November 19th, 2008, 9:41 am
by Mgardiner1
If i'm blowing spider gears on a Dana 35 with a stroked, 282 CID inline six, and the 8.25 is only marginally stronger..... I'm sure it won't last long at all.

Re: the limits of the 8.25

Posted: November 19th, 2008, 11:55 am
by SilverXJ
The 27 spline is only marginal stronger. The 29 spline is quite a bit stronger.

Re: the limits of the 8.25

Posted: November 19th, 2008, 2:39 pm
by Mgardiner1
SilverXJ wrote:The 27 spline is only marginal stronger. The 29 spline is quite a bit stronger.
27 spline was compared to Dana 35
29 spline was compared to being almost as good as a Dana 44

a Dana 44 is still not a good option for 460 CID IMHO

Ford 9" is the real deal

Re: the limits of the 8.25

Posted: November 19th, 2008, 4:20 pm
by yuppiexj
I would say for true abuse D60 or 8 3/4 are the way to go.

Re: the limits of the 8.25

Posted: November 19th, 2008, 6:25 pm
by Shark
this 8.25 is from a '95 so it doesnt have the increased spline count. i wont have lost anything if i break it. how long do you think it would last? i think traction might be a problem so that might help releave some of the torsion on breakable parts. this car will only weigh around 2000lbs and most of the weight will be in the block.

Re: the limits of the 8.25

Posted: November 19th, 2008, 6:29 pm
by Mgardiner1
LOL if you keep doing one-wheel-peel's then it may hold up for lil bit. 2k lbs is pretty light. I bet the first time the car hooks up on a launch, it grenades the spider gears

Re: the limits of the 8.25

Posted: November 19th, 2008, 7:18 pm
by yuppiexj
Mgardiner1 wrote:LOL if you keep doing one-wheel-peel's then it may hold up for lil bit. 2k lbs is pretty light. I bet the first time the car hooks up on a launch, it grenades the spider gears
Then it's time for a "Lincoln locker"

I wish I had the time to assemble the spare XJ drive train into a buggy, rat rod, or some other crazy fun nonsense like that

Re: the limits of the 8.25

Posted: November 19th, 2008, 7:24 pm
by Mgardiner1
LOL Yes that sure would be fun :-)

Re: the limits of the 8.25

Posted: November 19th, 2008, 7:37 pm
by John
Sounds like you will be changing rears twice, I am not as concerned with spider or side gears as I am with the shafts.
John

Re: the limits of the 8.25

Posted: November 19th, 2008, 7:55 pm
by Mgardiner1
I think it holds true in almost any axle, but the spider and cross shaft generally tend to be smaller then the shaft of the axle. i dunno. It seems more common that people break axle shafts. Yet i blew apart the differential assembly, and both shafts are fine

Re: the limits of the 8.25

Posted: November 19th, 2008, 8:28 pm
by John
You get housing flex for free with a 35.................
John