Moparts
Where do you draw the line with stock 8-3/4" axles?
Posted By: StealthWedge67
Where do you draw the line with stock 8-3/4" axles? - 02/16/12 07:53 PM
..... And am I close to that line? Strattling the line? Over the line?
Here's the particulars:
Full weight (3775# with me in the seat) '67 B-Body. Street / Strip car, running 255/60 drag radials. 451 / 727 combo, footbreaking. Ran 12.0's last year with a 1.70 short time. A few mods this winter should put me in the 11.80's and maybe 1.68 60's (??).I'd like the car to eventually run solid mid-11's.
It has a fresh center section with 3.91's and an Eaton clutch sure-grip unit. The stock axles looked fine with no visual evidence of twist when I had it apart in the fall.
So where do I stand?
Posted By: reknapp52
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 08:15 PM
You'll probably start breaking the ring and pinion before the axles give you trouble. Keep an eye on the axle splines, they will twist quite a bit before they will break. That is my experience from running a small block with 4-speed years ago.
Posted By: kissmyaspen
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 08:20 PM
My dads 67 satellite has been 11.70's 1.56 60 foot with stock axles.. Only broke one and it has a spool in it. Its getting mosers soon.
Posted By: 383man
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 09:41 PM
How often to you plan to race ? I ask because if you are like me and just do a few T & T races or some local races which for me is about 2 to 4 times a year I might race my 63. This year I had it out 3 times running high 10's and you know I have raced my 63 a few times a year since 2006 and even the old eng ran mid 11's. My point is my axles still look fine with no twist at all on the splines. I am seriously thinking I may want to go to a Dana now that it has run 10.70's and I hope to drop that et some but the rear is still holding up. Course if I raced alot I would not hesitate to go to a Dana. But if you only race a few times a year you may be fine in a mid 11 car. And I am using a Detroit Locker with stock axles. Course it will never hurt to upgrade because if the rear does break you best pull the trans and check the overrunning clutch if its an auto. Ron
Posted By: wafflebatter
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 11:00 PM
my roadster has an 8 3/4, moser axles, strange center, back brace, car has been 5.52 @ 123mph in the 1/8 with a 1.18 60ft,
I'm sure I am pushing it to max limits, but the car only weighs 1900lbs
Posted By: Mroctober
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 11:02 PM
Quote:
You'll probably start breaking the ring and pinion before the axles give you trouble. Keep an eye on the axle splines, they will twist quite a bit before they will break. That is my experience from running a small block with 4-speed years ago.
2X, 4 Speed 11.90 Dart on the street !!!!!!!!
Posted By: Cab_Burge
Re: Where do you draw the line with stock 8-3/4" axles? - 02/16/12 11:28 PM
A SB 4 speed car will break axles a lot quicker than a BB car of the same weight with a footbrake 727 trans. will
Been there done that, more than once
Posted By: JohnRR
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 12:13 AM
Quote:
..... And am I close to that line? Strattling the line? Over the line?
Here's the particulars:
Full weight (3775# with me in the seat) '67 B-Body. Street / Strip car, running 255/60 drag radials. 451 / 727 combo, footbreaking. Ran 12.0's last year with a 1.70 short time. A few mods this winter should put me in the 11.80's and maybe 1.68 60's (??).I'd like the car to eventually run solid mid-11's.
It has a fresh center section with 3.91's and an Eaton clutch sure-grip unit. The stock axles looked fine with no visual evidence of twist when I had it apart in the fall.
So where do I stand?
How much racing are you planning on doing ? the better you 60 ft the bigger the chance of twisting the axles , luckily with an 8.75 the axle will not exit stage left when the end twists off .
I'd think about changing when funds allow.
Posted By: StealthWedge67
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 01:04 AM
You guys bring up a good point: I'll only race 5-6 times a year if I'm lucky. Sounds like the consensus is that I'm fine for now. I'll make a point of checking the axles each winter, and spend the money on something else.
Thanks as always, guys.
Posted By: Sledge_57
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 01:13 AM
Quote:
..... And am I close to that line? Strattling the line? Over the line?
Here's the particulars:
Full weight (3775# with me in the seat) '67 B-Body. Street / Strip car, running 255/60 drag radials. 451 / 727 combo, footbreaking. Ran 12.0's last year with a 1.70 short time. A few mods this winter should put me in the 11.80's and maybe 1.68 60's (??).I'd like the car to eventually run solid mid-11's.
It has a fresh center section with 3.91's and an Eaton clutch sure-grip unit. The stock axles looked fine with no visual evidence of twist when I had it apart in the fall.
So where do I stand?
On the edge
Maybe the Sure Grip will help save them (I have a locker) but my 67 broke an axle the day I dipped into the 11's.
I had 4 passes that day, a 12.2, two 11.97's and a 22.42. Guess which one the axle broke on 
Replace the axles, when the stock axle breaks you'll be looking at possible trans (sprag) problems too.
JUST DO IT...... 
Posted By: Mopar-Al
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 01:32 AM
My 72 cuda was 3780 with me in it. Went 9.82 with a 1.31 60 ft I had a spool, 430 gear and moser axles. all new, went about 5 passes and ended up having serious back lash in the gears. Went straight to a dana the next race. I was trans braking tho, and leaving at 5500. My car went on a 1200 lb diet, so things are good.
Posted By: Eric
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 02:01 AM
Quote:
my roadster has an 8 3/4, moser axles, strange center, back brace, car has been 5.52 @ 123mph in the 1/8 with a 1.18 60ft, I'm sure I am pushing it to max limits, but the car only weighs 1900lbs
So build a motor with more HP... 
...that way you will know for sure... 
...oh thats right..you're doing that already. 
Posted By: Rapid340
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 02:06 AM
I've heard of a fair amount of aftermarket axles breaking lately in applications they shouldn't. You might be better off with known US made steel axles (stock ones), even if they are 40 years old.
Posted By: The Shocker
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 02:37 AM
One of the hardest things on axles (especially stock axles) is not the hard launches it is running a spool IMO.I broke many stock 9 inch Ford axles in street cars running a spool on the street (and sum of them never got raced on a track).What i mean is people run a spool for a while and twist the axles ,and the first time they get a good launch they snap and people assume the launch is what broke the axle when infact the axle was already weak from the sharp turns with the spool.I got so good at changing them i would pull the other side axle out and then run a long dowl rod to knock the broken piece of axle out .Then i would run a broom handle with a magnent taped to the end down the axle tube to retreave the piece .I could change the axle without dropping the chunk out this way and be back on the road (hey i was a teenager ,lol). They all twisted off right past the splines and i broke the biggest part of them on the left side .The reason the left side breaks most is because of the sharper turns that take place to the right on the street.My Dart drag only car has an 8.75 and im running a spool and 35 spline Moser axles ,but im still easy with it and take 3 point turns off the trailer ,onto the track ,etc when i can.I also inspect my axles for signs of twist at the end of each season ,but the 35 spline Moser's are still straight as an arrow after 5 seasons now ...
Posted By: clovis
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 03:00 AM
My 8 3/4 has probably 300 passes on it with stock axles and a spool. I'm about 3400 lbs, footbrake and ran high 10's-still has no signs of twisting. With the new motor I went ahead and put a Dana in, as the difference in price when starting at ground zero is pretty nominal.
Posted By: Triple Threat
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 04:14 AM
We raced my dads challenger for lots years with stock axles, Heavy car, went 1.63 best and 11.90's. Never hurt the axles.
You SHOULD be fine.
Posted By: dizuster
Re: Where do you draw the line with stock 8-3/4" axles? - 02/17/12 09:02 PM
If it makes you feel any better, I'm going to foot break my near stock weight '62 B-body with a turbo small blocck and stock axles this year.
Worst case it breaks one and I have to take the trans back out to check the sprag... but I'll have a few weeks while I'm waiting for the Dana to be built at that point... LOL...
I know my Dad's roots blown small block Volare at 3785lbs went HUNDREDS (4,5,600?)of runs and never broke an axle in the mid 11's. It had the same axles in it for 25 years before we hopped the motor up to the 11.0's and put some chinese replacements in it.
8 3/4 are a lot better then people want to give them credit for. As mentioned, sticks/trans brakes, and spools give them a bad rep'.
I broke my buddies in his '62 12.20 Plymouth... but it had a spool.
Posted By: Defbob
Re: Where do you draw the line with stock 8-3/4" axles? - 02/18/12 10:30 PM
I snapped a pinion in my convertible..... on the street. BUT I am aggressive with the 4speed. The car runs 11.54 @ 116mph, 1.70 60' with 3.55 gears. I now have Richmond 4.30 gears.
Dana 60 is coming soon.
Posted By: 440Jim
Re: Where do you draw the line with stock 8-3/4" axles? - 02/18/12 10:34 PM
It didn't take long to break a stock 1973 axle in an 8-3/4 on my 'Cuda. About 3700 lbs, 440 CID, high 11's, 1.55 sixty foot, 3900 stall converter, 10.5 slicks.