8.25 build

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Parts ordered and will be shipped tomorrow! Cass (Doctor Diff) set me up with gears, master install kit, and 29spline track lok carrier. 29 splines axles will be ordered in two weeks. Next up is remove pinion and axle bearings/seals then clean and prep housing for new parts.
 
75ddart said:
Hate to hi jack this thread, but that's impressive being a big block car , and keeping the 8/14 together. I have an 8/34 A body rear with 3 different center sections which to choose from. My car currently has a 8/14 in it and would like to stay with that, but it's an open 3.21. Been thinking or some track time next year with this car. Stock 360 and street tires, and possibly dot type slicks, just not sure yet of my options. Sounds like the 8/14 can take some punishment. I just wonder if running an open diff would make much difference than a sure grip with decent to good track prep and street tires with a stock engine.
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Without a sure grip you won't have any traction.lose up to 2 seconds off your time.
 
It hasnt been said yet but i had richmond 4.10's (& 4.56's) in my old 76 dart with the 8.25 & somthing they (summit or richmound) NEVER mentioned is the the cross shaft (the shaft that holds in the C-clips will halfta be eather ground off a little down the side or get a cross shaft thats already made that way) The problom is the ring gear is soo thick it covers a small portion of the hole the pin goes into the carrier. Found that out when i went to re-install my c-clips wansnt happy!:violent1: i ende up goen to the bench grinder & making a flat spot about 1/4 inch wide or so just to clear the gear \. Just an fyi man!
 
I was prepared for that. I have a newer 8.25 in my jeep Cherokee and have heard of having to do that with the higher gear ratios. But thanks for the info so others looking to do this type of build have an idea of what's involved. I'll be doing 4.56 gears from motive gear.
 
Well gears and install kit made it here today. Still waiting on locker thought. I will make more progress this week end. I'm off for almost two weeks for the holidays so should have rear fully build by early January. Got some cleaning done in the shop today.
 

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Locker arrived yesterday, so today I will be removing the pinion, bearings, and cleaning the housin. Then I'll be dropping off at a buddies place to have the tubes and new perches welded.

Here is picture of track lok and 4.56 ring gear. Ring gear is way thicker than the stock 2.71 ring gear.
 

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Here is a little info for people that may be in the same boat as myself....Tired of hiway gears. My 7.25s have all been 2.94, and my 273s and 318s have destroyed 3 rear ends. One wheel peals and what feels like an unlimited top end while still enjoyable left me wanting more. I went down the 8th mile track this year in a 55 Chevy truck with otherwise stock 350 in it. 11years in my barracuda and not one run down the track? Its time to move forward! I set a goal for my self of high 12s low 13s. Or 8.26-8.5 in the 1/8. So here we are setting up the rear to handle my goal. The motor will receive its upgrades middle of next year but will remain the 273 I have in place.
 
I plan to drive this to the track and some mostly local street driving. So I did a compare to my old tire size/gear ratio to new tire size/gear ratio with my 4 speed.
-------(2.94)----------...........--------(4.56)---------
235/60/14=25.1dia...........275/60/15=27.99dia
__________________________________________________
110mph-4,329rpm...........110mph-6,000rpm
..80mph-3,148rpm..............80mph-4,375rpm
..70mph-2,755rpm..............70mph-3,828rpm
..60mph-2,361rpm..............60mph-3,281rpm
..50mph-1,968rpm..............50mph-2,734rpm
..40mph-1,574rpm..............40mph-2,187rpm
..35mph-1,377rpm..............35mph-1,900rpm
..25mph---984rpm...............25mph-1,367rpm
 
75ddart said:
Hate to hi jack this thread, but that's impressive being a big block car , and keeping the 8/14 together. I have an 8/34 A body rear with 3 different center sections which to choose from. My car currently has a 8/14 in it and would like to stay with that, but it's an open 3.21. Been thinking or some track time next year with this car. Stock 360 and street tires, and possibly dot type slicks, just not sure yet of my options. Sounds like the 8/14 can take some punishment. I just wonder if running an open diff would make much difference than a sure grip with decent to good track prep and street tires with a stock engine.
Click to expand...

I've got 8.25 - Sure Grip and 4.10 behind my 383 in the Duster and it's been put thru some punishment and not an issue with it yet...
 
Pana.Mopar did you upgrade your axles from 27 to 29 spline? Just curious if people running 8.25 behind strong combos have been running stock axles.
 
ProStocker273 said:
Pana.Mopar did you upgrade your axles from 27 to 29 spline? Just curious if people running 8.25 behind strong combos have been running stock axles.
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I'm running stock axles dude. I'm sure there's a chance they will go after 100 passes on the strip but so far they are holding up well.
 
That's cool, I think most people are. I figured with my 4speed I would need the extra strength. Nice thing is my car is under 2800lbs and I still have some weight to pull out of it, so I think this rear will hold up well. Thanks for the reply. I am curious if others are running stock or upgraded doctor diff axles?
 
Got pinion and yoke off and started cleaning up housing to have tubes and new inboarded spring perches welded up. 29 spline axles will be ordered tomorrow. :burnout:
 

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Housing stripped and ready to have the tubes welded. Got axle bearings and 2" screw in wheel studs today. Now just waiting for 29spline Dutchman axles to show up.
 
29 spline axle shafts finally came in from Dutchman motorsports in Idaho. Now just waiting on housing to be welded up. Should have it back by the weekend. Axles shafts don't neck down like the stockers.
 

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Measured up new shafts compared to old shafts
......,................................. Old____________________New
C-clip grove diameter: .700-------------------.750
Spline diameter. : 1.158------------------1.245
Shaft diameter: 1.055-1.230-1.480-1.620-----1.245-1.310-1.620

I'll have to check on the material new vs old but it is for sure a improvement over the old. Which from what I have gathered, most people are using stock shafts without a problem. Looks like I'll be ordering some new c-clips for the new shafts on friday and begin assembling this weekend.
 

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As you can see from my previous post i put 2" screw in wheel studs with lock washers and installed them with some loc tite. Picking up housing on wensday. I just had tubes welded. I'll be in boarding springs at a later date so new perches were not welded on yet.
 
Got my housing back with the tubes welded up. I have decided to just do the mini tub and spring location first so I'll be moving a little slower on assembly of the 8.25
 
Well no progress on the assembly of the housing, but got my S,S springs. I went with the 863-864 springs . Also in the mail is Reilly motorsports spring relocation boxes. I like these boxes for one the price and two I will be able to set the axle back an inch to center wheel in the wheelwells!
 
I have a stock 8.25 with 3:55. As soon as I get the motor back in and the slicks mounted I'll let you know what I break. I'll be running a 400 hp small block but it's and automatic car.
 
Prostocker, I love the fact that you are committed to building a tougher 8 1/4 rear. don't take me as being a know it all here. however, for $1,000 you could be in the ball park of a built 8 3/4 and be so much stronger for future upgrades. not to mention doing away with C-clips, rear cover type installs, and having so many more options to aftermarket parts.

I suffer from heading astray on some of the parts of my builds at times, and have to have buddies jerk me back to rational thinking when I get committed to something that has a better option for the same or only slightly more money.

just putting that out there, but I know you have already bought the parts and are in full commitment at this point. I still will be following your build and hope that the rear takes all the punishment you can give it and then some!
 
8-3/4 is twice as much to build. He'll a Dana 60 is cheaper to build. But I'm building my car light and racing with my 273 for awhile so I'm sure it will hold up to some 4speed launches.
If I have to build another, I'll probably go with a 9"!
 
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