8.25 build

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ProStocker273

ProStocker273

MoPar N Jeep
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Im building a 8.25 from a 74 dart. Its a Canadian rear end with 11" drums and 2.71 carrier. Thank you Commando66!!

My car is 65 barracuda 273 (for now) aluminum flywheel twin holleys on a tunnel ram with a 4spd. Now my year 4speed(1965) has the low 1st gear set. Last year for the 3.09 first gear.

Ill be doing some 1/8 mile runs next summer and am still not sure what gear ratio I want to run. My car is around 2800lbs, and will be mini tubbed before rear is installed, and tires will be 28" diameter.

Have a line on a Richmond ring and pinion 4:30 ratio (worried about the install with this ratio) most jeeps above 4:10 have to grind down a tooth to install ring gear)

Second is a 3:73 ring and pinion. I figured this would be a good ratio for driving to the track and shows, as well if I have to upgrade to a 8-3/4 a 3:73 in the 8.25 would appeal to more people as far as resale/trade.

Just looking for opinions/experience on what to run. I am open to other ratios and other suggestions on putting this rear together. Still looking for c-clip eliminator.

One thing to remember is my first gear ratio. It is 3.09, unlike 66 and later A833s.

Thanks for any help in advance.

After all parts are chosen and delivered ill do a step by step pic by pic for those who are looking to building a 8.25.
 
I know everybody's tired of my 74 Duster.
But how can you go wrong with a car that works.

I had a 8 1/4 in the Duster for 300 plus pass's.
50 pass's of 100 shot out of the hole with NOS.
12.21 off the juice 11.59 with.
No C-clip eliminator's
Gears are 3.91's on 11.50x 26 inch Hoiser QT pro's.

440 engine
727 trans.

Since you are going to use a manual trans I would go with pro-gears= racing gears.

 
Sweet duster. Pro gears? Are you referring to manufacturer/quality.
Richmond's gears in the 4:30 ratio is recommended for racing. (Not the ratio but the ring and pinion)

Ill have to check on the 3:73 ratio but I do recall they are Usa made.

Im leaning towards the 4:30s as most commandos and d/darts ran a 4:86 out back. I'm just a little concerned my first gear(3.09) with the aluminum flywheels and my car being real light a 4:30 might cause more of a traction issue or run out of gear if I take it down the 1/4mile.
 
Buy gears that are Made for drag racing.
Stock gears and a 4 launching at high rpm's will not last long.
 
This is gears I was looking at. Not sure if they are oem or race?

[ame]http://m.ebay.com/itm/271136263768?nav=SEARCH&sbk=1[/ame]
 
This has my interest. I raced my 8.25 all summer with street tires and was told a million times that slicks would break it. Let me know how yours turns out. I was running low 14's by the way with a best sixty foot of 2.34��
 
Since my kids are out of the house the Duster has gotten a Dana 60 and a 512 ci. Engine
And a Caltrack rear end kit.
 
I have looked for a spool but have not found one myself. If they do make them I would love to know where to get one. I work in a cnc shop and was thinking about making one, but I think it would require a c-clip eliminator which I have yet to find also.

I have decided on the 4:30 gears, ill have them by the end of the month.

I know some people like to upgrade to the larger 11" brakes that are on my axle but I'm looking for the smaller 10" to help keep the weight down. If anyone local has all the 10" stuff and wants to trade let me know.
 
Okay here is picture of brake hard ware. (For reassembly reference)
 

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Removed all hardware including 4 bolts for backing plate. After removing everything but axle and loose backing plate its back into the diff housing. Remove the bolt holding cross shaft pin. Should be able to see bolt in picture here.
 

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You should be able to finesse bolt out then push cross shaft pin up and out from underneath fairly easily. At this point the smallest 2 of the spider gears can be removed.
 

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Next step is removing the c-clips. Gently push on axle shaft towards center diff with your other hand waiting on c-clip. Or you can push in and let it drop then fish it out as I did.
 

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As far as removing the carrier remove the four bolts while keeping track of left and right caps. One had a w44 the other side a w43 stamped on it. And all that's left is removing pinion/yoke.
 

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This picture here shows the smallest diameter of the shaft at 1.055". Now the rest of the shaft is much larger as you move out towards housing ends(1.480). Does anyone have a a-body 8-3/4 shaft to measure the smallest point?or a 7-1/4? Just curious, got to say I started pulling out axle shaft thinking wow this looks stout. Then it necked down a bit. I still have no doubt this should be a strong setup. But with some MT sportsmans and eventually a stroker, the axle shafts do seem like they would be the weakest link. Only time will tell..
 

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womanator said:
I know everybody's tired of my 74 Duster.
But how can you go wrong with a car that works.

I had a 8 1/4 in the Duster for 300 plus pass's.
50 pass's of 100 shot out of the hole with NOS.
12.21 off the juice 11.59 with.
No C-clip eliminator's
Gears are 3.91's on 11.50x 26 inch Hoiser QT pro's.

440 engine
727 trans.

Since you are going to use a manual trans I would go with pro-gears= racing gears.

Click to expand...

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.
 
Leadfoot has a wicked combo and a 8.25 out back, i dont remember much about it though
 
Make sure to check the thread-in carrier adjusters. I've cracked two sets in my 4 speed, small block on street tires.

I made a tool for adjusting them. A 4 foot steel bar stock with a 1/2" drive socket welded in reverse on one end for a ratchet. On the other end I simply welded a large nut that fit inside the hex adjuster. Works awesome for these rears.
 
Thanks 80FBody. And 75DDart from all I have learned with a 8-1/4 it will hold together better with a track look or Detroit than with an open carrier. All commentary is welcomed.
 
Thanks for the link. And thanks again, I can't wait to get that 7-1/4 out from under my barracuda. I'm still on the hunt for steering wheel or 66 manifold for ya.

Next is remove pinion and yoke and although bearings look to be in real good shape I'll be removing and putting new ones in as I want to do this once.

Also this coming week end I am picking up a set of bbp disk brakes for $100. Wasn't looking forward to 10" drums in the front and 11" in the rear. Problem solved.
 
For you guys that have ran or are running an 8.25, are you using the upgraded 29spline a-body axles?

And what are you running as far as a locker?

I have priced everything out
4:56 gears & master install. $300
29spline abody axles with 2" studs bearings/seals. $300
track lok clutch style locker. $300
+ shipping. $100
Total. $1000

That's a few hundred more than I had budgeted for mostly because of the 29spline upgrade. I know a Detroit locker would be a better choice but I figure ill through the track lok in my jeep and a Detroit in the barracuda when the 360 is ready to go in. This means no leaf spring relocation or mini tub for now.

Ill be ordering parts Friday or Monday and make some more progress.
 
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