8.25 rebuild - Any tech advice?

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superdart

superdart

Shade Tree Tinker Gnome.....
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I am finally getting ready to rebuild and upgrade the 8.25 in the Dart. Below is a list of what I am already planning to do to it (don't talk me out of it, I already have the parts).

I have never worked on a car rear end (just big stuff on Class 8 trucks) but the theory is the same. Also, a buddy is helping me who use to work at a dealer and knows 8.25s and 9.25s very well.

My plans:

Jeep GC disc brake upgrade (along with 11.75 front disk upgrade)
Post-'97 factory Suregrip (29 spline)
New axles to go with the new Suregrip
LPW Diff Girdle Cover
Stud the Carrier caps
3.55 gears
Motive Gear axle rebuild kit

I know the new Suregrip is 29 spline versus the factory 27 my car currently has. However, my car has 2.45s so getting a carrier was a must in order to change gear ratios. The carrier was brand new from a dealer for $40 (going out of business) so I can justify the cost to get axles made. It also works out because I will get the axles cut with the Jeep GC register hole, eliminating the need to grind out the holes on the Jeep rotors to fit the Dart axles.

I was also thinking about welding up the axle tubes to the carrier housing. Good idea? Bad idea? I have a welder, so it's not a big deal to do.

So, any tips, tricks, suggestions, things to watch out for?

The car is only a 360-ish HP, and even if I upgrade will probably never see more than 400, so I already think I am over-building it.:toothy10:
 
i dont have really anything to add besides im getting ready to build my 8.25 also....
27 spline suregrip with 4.11s
stock axles for now--- (but may grab some jeep 8.25 yukon HD axles to be cut to length at a later date)
LPW Ultimate cover

-- i wanted to ask what you achieve by studding the carriers caps ?
 
Just a little more strength/thread contact. It's easy & cheap so I figure why not? It might be over kill considering the girdle cover....but I am not generally one to under-engineer. :toothy10:
 
was there a stud kit for that ? and yes, that cover is a brute.
i was looking at a different one, same concept, but i like that one much better.
 
LPW sells stud kits for 7/16 and 1/2 inch applications (think we need 1/2) for $26.

But I'm sure I can get the same type of stud locally (Grainer or Fastenal) for less. If I get something I'll post the part numbers.
 
cool, and i will tell you i havent talked to too many guys that now much of anything about the 8.25 rebuild. but im with you on under engineering.. im sure i will find the weakest link in the 8.25 at some point, then will see if i can make is stonger.
i did read in stock form, the 27 spline suregrip unit can hold up to 500 crank hp...
 
I am only working in the 350-400hp range for this car, so I figure this build will be more than enough. As long as one is not running slicks, the tires will spin before something in the axle gives out. :toothy10:
 
why has no one chimed in on this? Its been 3 days since this has started:angry7: I'd love to know more about building myself a proper 8 1/4:cheers:
 
most upgrade to the 8.75 so there isnt too many trial an error reports on the 8.25....
so i guess i will create one along with superdart, with the few improvements that superdart is doing he should have a fairly stout rear end. Im going to run mine as a 7 spline suregrip 4.11 till i break something. im considering upgrading to the LPW axle braces also.
 
Mopar Action February 2004 edition had an article on building the 8-1/4. I have it in PDF and will email it to you both.

I could link it here if the Admin gods allow it (Copyright issues?).
 
yeah, finding an 8 3/4 is hard to come by and the people who have one refuse to give up their sources as to where they got theirs or refuse to sell one out of their stash of 8
 
well seems its just the A body version that is getting harder to come by, There is a guy here in South Tucson that has a few of them, and will sell them at the going price, 600 to 1000 buks dependent on whats in it.

also.... anyone seen a c-clip eliminator kit for the 8.25 ?? I was reading its a good upgrade for this rear.
 
I'm in the slow process of doing a 73/74 A Body 8.25. Bought a used Grand Cherokee rear disc set-up and am in the process of enlarging the caliper adapter and dust shield to fit the A Body. Bought all brand new GC calipers, e-brake stuff, rotors, etc. Got a good deal on a Sure Grip unit and a set of 3.55s instead of using the 2.71s that came in it originally. Still got to get new bearings rather than use the old stuff. So gonna follow along on this thread too.
 
I've got an 8.25 in my 69 Valiant and although I am doing a stout 340 for it, I would like to keep this rear in the car. I am very interested in how much this rear can handle and how well it can be built.
 
Revhendo said:
I've got an 8.25 in my 69 Valiant and although I am doing a stout 340 for it, I would like to keep this rear in the car. I am very interested in how much this rear can handle and how well it can be built.
Click to expand...

from what ive researched and read through out, the lighter the car, the more abuse the 8.25 can take in stock form (under 3000 lbs) noted in muscle car mag, engineers stated it could handle up to 500 crank hp as is with the 27 spline suregrip. The LPW girdle is the strongest bolt on upgrade you can find to help keep things in place. and upgrading to the 29 spline suregrip and axles would make it stronger... Also noted, the old school drag cars ran this rear due to its light weight and cost of parts is cheaper than the big brother 8.75.

besides studding the carrier and the LPW girdle cover and tube brace, im trying to find a C-clip eliminator kit, as the C-clip may break first and release the axle from the housing.
 
I was wondering about C-clip eliminators. Will that affect the Jeep disc conversion?
 
I believe moser has "c" clip eliminator packages. Interested in the PDF file also which can be sent to tepidoratoratyahoodotcom. West coasters have the advantage of good parts supply in the self serve junkyards that rotate their stock every two weeks or so (less here in Tucson). Have any of you invested in the pinion depth setting tools? For most typical street applications these rears are plenty strong. The first few years I owned my car I bracket raced it every other weekend and have not had a failure yet. The Valiant Patrol scales at 3680 lbs.. (no one said police cars are light) I agree that some stock class racers I know have switched back to them to save on cost and weight and are not unhappy they did so unless they race at lot of different tracks where they might like the ability to easily regear the car that the 8.75 provides. I'll be watching this thread for more info. Thanks Superdart/others.
 
probably need to call moser and talk to tech folks, i didnt see a specific kit for chrysler.
 
I think the C-clip eliminator would mess things up for the brake upgrade.

However, I really don't think it's necessary. How many 8.25 and 9.25 C-clips equipped vehicles are roaming about the world? (Every late A/F/M/J plus all the Jeeps and Rams). How many C-Clips have you seen brake?

One of the advantages of the '97-up 29 Spline carrier is that it uses a larger C-clip (for the trucks) making it more durable. To me, the concern of hub retention in the event of axle breakage is a moot point. I will spin the tires before I will ever snap an axle (remember, I am ordering axles).
 
true, true... id like to order a new set of 27 splines that are better than stock, once i get the current axle length i can take a look see.
 
I would definitely recommend it as the factory 27 spline axles are tapered, whereas anything you order (as well as the 29 spline Dakota axles) are straight shaft with no taper.

Talk to Doctor Diff. I will be getting my axles from him since he knows Mopars and can get axles made cheaper than Moser or Strange. Might not be "as tough" but in reality they are WAY overkill for my needs. I did the math and the cheapest Moser axles can take something like 300% more torque than my car can make....LOL.

I bought my C-body brake upgrade lines and brackets from him....helluva guy.

http://www.doctordiff.com/
 
thanks for the link, i just emailed him to see what he can do

-----------wow.. i emailed him at 6:30 and had a quote by 7, and a not so bad quote either..
27 spline HD axles with 3in studs for $ 245 plus shipping, and 3 a day turn around. guess im doing a ring and pinion and axles on the same day now !!
 
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