Stock axle strength/ how fast are you with them

[RT K_line]

I'dlike to know about stock axles strength. I'm planning on run nitrous again just with the big shot upgrade. Not sure yet how much though. I've always hit it in 2nd because I don't want to break anything off the line. I'm running 3.55 with a 3600lb car and want to run a 200hp hiT off the line or more with a progressive controller. Engine ;mild 440.

 

[bobtile]

What rear?
I twisted my splines on an 8.75 running about 400 hp to the wheels on my GTX.
That was street/strip with M/T et streets.

 

[RT K_line]

8 3/4 rear end

 

[mmissile]

For the few hundred bucks it costs to have more security against a catastrophic event, I'd say it's a no brainer on the smart move.

 

[66Satellite47]

Well, when I bought my '65 Coronet 426 W 4spd it had an axle with splines turned 15+ degrees. Don't know how the NO2 affects things.

 

[dvw]

I ran my 11.0 auto Volare for years on stock axles. My 4 speed 12.50 Challenger put one spline Worth of twist in 100 passes. Never broke one completly.
Doug

 

[dvw]

I ran my 11.0 auto Volare for years on stock axles. My 4 speed 12.50 Challenger put one spline Worth of twist in 100 passes. Never broke one completly.
Doug

 

[66Satellite47]

Yup, a 12.50 car can twist a stock axle. If you got more & go faster, axles are a weak point. Bigger HP surely need aftermarket axles.

 

[moparcrazy]

What rear?
I twisted my splines on an 8.75 running about 400 hp to the wheels on my GTX.
That was street/strip with M/T et streets.

YUP ME TOO !!

 

[moparcrazy]

i bought Moser 35 spline Axels for my 8 3/4 with Spool and bearing's, as a kit for under $500.00

 

[Mike Gaines]

If any B Body (3600+ pound) Mopar makes more than 500HP (on nitrous or otherwise) you are probably going to end up breaking MORE than the 8 3/4 axles....you are going to break the entire rear end and probably take the transmission with it when it goes. I have seen three 8 3/4 Mopar rear ends blown out of the car just this year at the drags.
If you have a 3100lb A Body Duster or something like that the 8 3/4 might be ok.
In my opinion....don't spend money on axles for the 8 3/4. Don't spend money on the 8 3/4 at all....this is if you plan on having a car that makes more than 500HP and you plan on running it on the dragstrip where traction is going to break the rear end.
If you have more than 500HP and you just plan on driving it around on the street (not with slicks at the drags) the 8 3/4 is probably ok.
Save your money and buy a $2800 Dana 60 and put it in if you want to make +500HP with, or without, nitrous.
If you think about it Chrysler started putting DANA rear end under the race Hemi's for just this reason. They knew the 8 3/4 wouldn't last.
Less than 500HP the 8 3/4 is fine.
Just my opinion.

 

[dvw]

My Volare runs 11.0@123 and weighs 3880. It has never hurt an 8 3/4 though I bet it's close to the power level where it could. When I was build a pure race car it always gets a Dana. Street/Strip, the 8 3/4 can go a long way IF the pinion depth and pattern are good. Heck I've seen 11.0 cars break Dana's. That should NEVER happen.
Doug

 

[Budnicks]

For the early 8.750" axles pre 68 {especially early 60's},
are weaker than 68 & later axles too
{tapper maybe or the weak ends}
but if you make enough to justify beefing up a 8.750"
better off going to a Dana 60 or Strange S-60 even better yet...
For a dedicated race car...

An Alum. 742 carrier is $1000+
Axles in 35 spline $400 for good ones
a Spool is cheap $200, a Locker is $500+
Bearing changes & different yokes etc.
Trussing the axle housing etc. so it doesn't bend...
you might as well spent a few hundred to 1000 more & put a Dana 60 in it...
I went 8.56 @ 158, with that 8.750" set up, in a 3520# 68 RR...

I don't think I'd do it 5 rounds a weekend every week end thou either...
It was a great Street/Strip car, it's still running around Sacramento area too,
some almost 15 years later...
New owner claims it's still running hi 9's & low 10's, NA...
No N20 anymore so no 8's anymore "allegedly"...
He's a street racer, so I'm skeptical....LOL

I put 1800hp threw a 8.75" in my 23 altered, ran 6.90's @ 190 it lived,
that car was only 1800#'s too
but was far from stock too, had pro gears, spool, trussed, Big Bearings,
all Lenco pieces floater 40 spline {astroloy {spelling?} shaft material},
big forged yoke/collar slider driveshaft, Wilwood etc. &
was only like 33" long too...
Running 15 x 33" slicks, it lived & was really light, main reason I did it...
Cost just as much as a Dana 60 or trick Lenco 12 Bolt at the time,
by the time all said & done, but saved me 50#'s...

Moser makes a better trick fabricated trussed 8.75" Housings &
axle sets for like $1200 IIRC...

But again if you want to make absolutely sure & spend the $$$ wisely
go with a S-60 IMO...

I've broke Dana's too, just much harder to break...
{720hp NA & two 300hp Progressive N20 kits, spray bars & plate,
one for launch violently & one for down track, came in gradually}
Twisted the crap out of the housing axle tubes a couple times,
broke the carrier one of them times too...
Went to the thick tubes {IIRC} 3 x .357" axle tube material,
never had that issue again...

My Pro-Gas & T/S Outlaw P/S cars all had 9" Fords, broke a few of them too...

 

[65 3 times]

This is a very good discussion. Opinions on which is tougher on rear end. Foot brake or trans brake. ?? Dave

 

[66Satellite47]

This is a very good discussion. Opinions on which is tougher on rear end. Foot brake or trans brake. ?? Dave

No question, trans brake is tougher on driveline parts. Shock load is always harder.

 

[bobtile]

Mark williams makes billet caps and spanners that is supposed to help the 8.75 a lot.
I dont have any experience with this however.

 

[Dodge 330]

My issue wasn't with the axles but with the **** Auburn cone sure-grip and 7290 u-joints. With street tires it's not a big deal but 600 HP and sticky tires under it and you will quickly find the weak points!

 

[HEMI-ITIS]

Stock Dana axels can handle over 1000 ft lbs of torque.

 

[khryslerkid]

What's the rules and regulations on axels at sanctioned race tracks?

 

[RT K_line]

Well thanks for all your helpful information. It sounds like no nitrous off the line until I can budget in a rear end upgrade. I mostly drive on the street to local Cruz ins with minimal track time so far. That may change after I finish painting the R/T.