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Axles design limits???

alfaitalia

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Can anyone post a definitive link to a chart or table that has the actual design limits quoted by the factory on Charger axles. I have a 8 3/4 but ive been offered a Dana 60.....over here they are an outrageous price. I wont say how much or you would laugh. I basically want to know the horse power and torque limits of both those axles top see if the gain is worth the cost. This car will NEVER see a drag strip (or be fitted with slicks etc) and will just be an enthusiastically driven street car. How much power are you running through your 8 3/4 ? I guess Im trying to persuade myself I don't need to spend the money.....but I will for a big gain on power handling and reliability. Even getting an axle upgrades here is not easy....not many live axle specialist this side of the pond.
 
Can anyone post a definitive link to a chart or table that has the actual design limits quoted by the factory on Charger axles. I have a 8 3/4 but ive been offered a Dana 60.....over here they are an outrageous price. I wont say how much or you would laugh. I basically want to know the horse power and torque limits of both those axles top see if the gain is worth the cost. This car will NEVER see a drag strip (or be fitted with slicks etc) and will just be an enthusiastically driven street car. How much power are you running through your 8 3/4 ? I guess Im trying to persuade myself I don't need to spend the money.....but I will for a big gain on power handling and reliability. Even getting an axle upgrades here is not easy....not many live axle specialist this side of the pond.

From the man himself, Tony DeFeo:


:thumbsup:
 
You have an axle! That's a start.
Congratulations.
 
LOL....I saw that coming....but was not expecting it to be you...at least not first!

As useful as that video above was (and thanks for it 67charger383) has anyone got actual figures/specs for the axles. Ive googled it.....but there seem to be different figures on every page!!!
 
1500 ft lb continuous input for a dana 60 on the Dana website
 
I know several who go high 9's with an 8 3/4. It's not the axles so much but the gears. If you do not plan to run slicks and only street tires, don't worry about it and keep the 8 3/4. Sticky tires and doing 6k launches......go with the Dana.
 
With street tires a properly built 8 3/4 will live a long life. My 11.0 3900 lb street car has never broken one hundreds of passes on slicks. I should add I ran my 4 speed Challenger (12.50@110) for 100 passes on slicks. Broke 1 spider gear tooth. On the street it still has the original 3.55 sure grip it was built with from 1973. And I pound on it.
Doug
 
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Agree with cranky and Dvw, no slicks, no strip, no need for a dana. Nice to have though, and a stick shift makes the dana more desirable.
I have never seen actual numbers as to designed strength specs, only comparisons of axle dimensions and spline counts. Strangely enough, more/bigger is better.
 
With street tires a properly built 8 3/4 will live a long life. My 11.0 3900 lb street car has never broken one hundreds of passes on slicks.
Doug
Buddy and I ran a car with a stick and 8 3/4 but the launch was 6k and after shaving the teeth twice we went with a Dana. The teeth giving up started happening once we got into the low 11's. IIRC, the car was around 3400 at the time.
 
I am a true believer in a Dana 60 for drag use with big torque & sticky tires. However for a street drive, even with major HP & torque an 8 3/4 will be just fine with good gears, properly set up. Aftermarket axles will make an 8 3/4 stand up to a lot of abuse, especially if behind an automatic.
 
My '65 Coronet was a factory 426W 4spd extensive motor mods, with much drag use & slicks. I bought it with a broken 8 3/4 & 2 broken 4 spds. Immediately switched to 727 & rebuilt the 8 3/4. Later noticed the passenger side axle had a major twist in the axle splines. Put another stock axle in. But I was drag racing & I knew a Dana was the answer.
An aftermarket axle will be a big improvement to an 8 3/4.
 
If you can afford it go with the dana 60....If not 8 3/4 thats my take
 
What really matters is how much traction you will have. If you're making 500 HP and have 6" wide tires (Or TYREs) your axle will never see much stress. Once the tires actually grip, the stresses start to be applied to the axle.
I have 295 series tires with a sticky 100 treadwear rating. I have an automatic and an 8 3/4" axle but I am considering a 5 speed swap. Even then, I'm keeping the 8 3/4" axle. My 440/493 is a mild build, 10 to 1 compression and a MP 528 solid cam.
 
IMO...
I believe that the standard axle assembly for the Hemi engine and 727B was the 8-3/4", probably the 489 case UNLESS, the purchaser opted for the Dana 60 with 3.54:1 ratio unless a super track pack car then the ratio was 4.10. The Dana 60 was standard with the 4 speed car on either the Hemi or the 6 barrel engine. BUT...the axles are susceptible to twist due to shock loads (high RPM starts with sticky slicks). Becsuse the axle shaft material is an alloy, perhaps a chtome molly alloy and definitely heat treated for additional strength. There are other alloys available perhaps a SAE 4150 or 86xx alloy. Perhaps you should consider an aftermarket axle available from several suppliers such as Strange Engineering at:
www.strangeengineering.net check them out or call / e-mail them or a supplier of choice.
During my racing days, we would paint a white straight line on the axles from the outboard bearing land to the spline end. And periodically, pull the axles and check for twist and when there was a one (1) revolution twist observed, the axle was replaced. This would be subject to frequency of use and if bonzai starts were used. We had a heavy car, a Chevy Biscayne 2 dr post with a 427/425 HP and a M-22 close ratio 4 speed and 4.56 12 bolt rear, ladder bars and 90/10 front up lock shocks and 20/80 down lock rear shocks for weight transfer which heavily loaded the rear axles. Just my opinion of course.
BOB RENTON
 
Anecdotal evidence from here suggests that you stick with the 8-3/4 diff. I only know one guy who ever broke one - he was doing huge burnouts all day at the strip...gonna break doing that eventually. The car had been beaten to death all it's life...I should know, I owned it before the guy who wrecked it again. :)

A normal street given car will gain nothing from having a Dana, except a lot more weight. :D
 
Can anyone post a definitive link to a chart or table that has the actual design limits quoted by the factory on Charger axles. I have a 8 3/4 but ive been offered a Dana 60.....over here they are an outrageous price. I wont say how much or you would laugh. I basically want to know the horse power and torque limits of both those axles top see if the gain is worth the cost. This car will NEVER see a drag strip (or be fitted with slicks etc) and will just be an enthusiastically driven street car. How much power are you running through your 8 3/4 ? I guess Im trying to persuade myself I don't need to spend the money.....but I will for a big gain on power handling and reliability. Even getting an axle upgrades here is not easy....not many live axle specialist this side of the pond.
A true Dana 60 commands an outrageous price everywhere. If you have the 8.75 with a 489 case, I wouldn't worry about it. If you have the 741, I wouldn't push it too hard.
 
I completely agree with MoparDanMan, be sure you have the 489 case differential housing. I have purchased a nodular iron case for my 69 Roadrunner Pro-Touring project but I had an 8 3/4 in my 64 Stage III Plymouth 4 speed car that hit 802 HP on the dyno and never had a problem with it. I did have stronger axles and a back brace on it. It came from the factory with six leaves on the drivers and seven on the passenger side to act as traction bars.
 
An update to my previous post. I went back in my old books and found some casting numbers. If you have 2070741 it identifies the smaller 1 3/8th-inch-diameter, 10-spline pinion shaft. Generally only found in "A" bodies. The 2881488 and 2881489 were used from 1969 through 1974. The pinion shaft diameter on these rear ends was 1 7/8 inches, and these pinion shafts were either 10- or 29-spline. After 73 all of the 8.75's were the 489's Casting number 2070742 was used from 1961-1969 and has a 1 3/4-inch-diameter 10-spline pinion shaft.
 
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