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limits of stock driveshaft?
#2155053
09/15/16 01:19 PM
09/15/16 01:19 PM
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Joined: Oct 2008
Posts: 370
Suffolk County, New York
1mean340
OP
enthusiast
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OP
enthusiast
Joined: Oct 2008
Posts: 370
Suffolk County, New York
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For a small block E body. Anybody know how far most people push these things before they twist up? I'm going to run a driveshaft loop on my car, but I figured at least for a little while I'd keep the stock driveshaft/stock pinion yoke on the car until I can recoup some funds. The car is an auto and on drag radials but I doubt it'll be hooking up too hard and will see mostly street driving (I'll probably be able to pick up a good one before getting to the track as I doubt I'll make it to the track before next season).
HP wise I am hoping will be around 650 at the crank via procharger so no instant nitrous hit off the line or anything like that.
Last edited by 1mean340; 09/15/16 01:22 PM.
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155076
09/15/16 01:45 PM
09/15/16 01:45 PM
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Joined: Oct 2015
Posts: 570
UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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I can't tell you what the limits are but I can tell you that on my old Street/strip '71 340 Cuda with stock 8.3/4" posi, stock leafs with clamps on the fr segment, snubber, stock prop, u-bolts etc., a 4200 verter/4.30's and 10x28's it took a 250 shot hit off the line with ease with daylight under the frontrunners, so wouldn't think you'd have issues with your set up.
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155111
09/15/16 02:33 PM
09/15/16 02:33 PM
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Joined: Dec 2005
Posts: 11,747
Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,747
Fulton County, PA
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7260 joints? Stock slip yoke? A driveshaft coming out under power usually tears up your car a lot more than the price of a good shaft, and maybe even the car of the guy next to you. You can afford the power adders but try to get away with a stock driveline? Cruising around it may be OK. I would not want it in there at the track. Neither would I want to be close to it or be in the other lane.
If the results don't match the theory, change the theory.
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Re: limits of stock driveshaft?
[Re: CMcAllister]
#2155130
09/15/16 03:05 PM
09/15/16 03:05 PM
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Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
cudadoug
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master
Joined: Aug 2003
Posts: 3,245
Between a rock & a hard place
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7260 joints? Stock slip yoke? A driveshaft coming out under power usually tears up your car a lot more than the price of a good shaft, and maybe even the car of the guy next to you. You can afford the power adders but try to get away with a stock driveline? Cruising around it may be OK. I would not want it in there at the track. Neither would I want to be close to it or be in the other lane. Well then there is this ^^^^ On a related note: I once a tossed a stock driveshaft out of a mid 11-second car once due to rear u-joint failure. Cut a slick then took out the little piece of rubber brake hose on the rear end AND bent a shock on it's way out. First thing to go was the tail shaft of the 727. AND the guy in the other lane almost wadded his ride up trying to dodge it. 11 second car isn't fast. That is, until you are at 1000' and you have no brakes, one flat slick and the good slick has a light misting of the recently exiting trans fluid on it.
Last edited by cudadoug; 09/15/16 03:09 PM.
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155137
09/15/16 03:18 PM
09/15/16 03:18 PM
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Joined: Dec 2005
Posts: 11,747
Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,747
Fulton County, PA
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I have had to dodge driveshafts coming across my lane back in the "good ol' days" when all we had were stock shafts. Not a fan of that kind of action.
If the results don't match the theory, change the theory.
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155147
09/15/16 03:40 PM
09/15/16 03:40 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
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master
Joined: Oct 2003
Posts: 7,506
Az
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At 650 HP, a stock driveshaft is a time bomb waiting to happen.
Fastest 300
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Re: limits of stock driveshaft?
[Re: Crizila]
#2155148
09/15/16 03:42 PM
09/15/16 03:42 PM
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Joined: Jan 2003
Posts: 11,730
Portage,michigan
B3422W5
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 11,730
Portage,michigan
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At 650 HP, a stock driveshaft is a time bomb waiting to happen. Yep. Why people would want to debate that fact is beyond me. It's an accident waiting to happen.
69 Dart GTS A4 Silver All steel, flat factory hood, 3360race weight
418 BPE factory replacement headed stroker, 565 lift solid cam
Best so far, low 10.30’s 1/4
1.41 best 60 foot
6.56 at 104.17
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155348
09/15/16 10:21 PM
09/15/16 10:21 PM
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Joined: Feb 2006
Posts: 608
TN
1DGEMAN
mopar
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mopar
Joined: Feb 2006
Posts: 608
TN
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The drive shaft doesn't break it is the U joints. Like Cab said put solid joints in it. I had hundreds of runs on 7260 joints in a stick shift Duster and Demon NHRA Stocker never broke an U joint broke plenty of 8 3/4's. Of course when the rules changed and I could put a Dana in the car I went 1350 and aluminum shaft. I can't believe a slushomatic hits the shaft like we did back in the day with our high pressure clutches and 3 pad discs. Oh and the 71 Demon Cab is talking about was my old car that got switched to slushbox because the owner couldn't drive a stick.
Last edited by 1DGEMAN; 09/15/16 10:32 PM.
Real Men shift for themselves
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Re: limits of stock driveshaft?
[Re: 1DGEMAN]
#2155492
09/16/16 01:24 AM
09/16/16 01:24 AM
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Joined: Dec 2013
Posts: 4,706
Wichita
GY3
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master
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Wichita
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The drive shaft doesn't break it is the U joints. Like Cab said put solid joints in it. I had hundreds of runs on 7260 joints in a stick shift Duster and Demon NHRA Stocker never broke an U joint broke plenty of 8 3/4's. Of course when the rules changed and I could put a Dana in the car I went 1350 and aluminum shaft. I can't believe a slushomatic hits the shaft like we did back in the day with our high pressure clutches and 3 pad discs. Oh and the 71 Demon Cab is talking about was my old car that got switched to slushbox because the owner couldn't drive a stick. This! I killed a 7260 Spicer joint at the track a few weeks ago. Sheared one cross right off! I started using solid joints!
'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155507
09/16/16 02:00 AM
09/16/16 02:00 AM
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Joined: Feb 2003
Posts: 1,108
Massillon, Ohio
cudatom
super stock
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super stock
Joined: Feb 2003
Posts: 1,108
Massillon, Ohio
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The stock drivetrain can take quite a bit of power. More than many think.
For 14 yrs(1988-2002) ran a stock drive shaft in my 73 cuda that used a combo u-joint to mate to the dana I added. Was running 10 teens at 3500lbs, 1.41 60'but no trans brake.
Close friend ran the same stock shaft and combo u-joint in his GTX from 1988 till 2 yrs ago. He was running 9.7-9.8 at 3550lbs and a trans brake. Never lost one.
Both of us do understand we were playing w/fire and have since switched. We were lucky. Even though you probably will be ok why take the chance when you can get a new driveshaft that's built to handle the power for about $400. Lots cheaper than replacing a car.
Ok
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Re: limits of stock driveshaft?
[Re: 1mean340]
#2155685
09/16/16 01:27 PM
09/16/16 01:27 PM
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Joined: Jan 2003
Posts: 13,407
Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
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Posts: 13,407
Marion, South Carolina [><]
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I ran a stock driveshaft until my car went into the 10s at 3700 lbs. Then I twisted two shafts on back to back weekends. Took out the tailshaft housing both times too.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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Re: limits of stock driveshaft?
[Re: 10secchallenger]
#2155774
09/16/16 03:07 PM
09/16/16 03:07 PM
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Joined: Mar 2007
Posts: 3,288
West Coast, USA
jbc426
master
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master
Joined: Mar 2007
Posts: 3,288
West Coast, USA
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Strange Engineering can ship you out a 3" chromemoly shaft with 1350 u-joint and forged yoke & flange for pretty cheap. If you don't want to spend the money, follow Cab's advice about the u-joints on yours.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: limits of stock driveshaft?
[Re: dogdays]
#2155853
09/16/16 05:53 PM
09/16/16 05:53 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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One thing unmentioned so far is shaft speed. If the gear numerical ratio is increased the shaft spins faster and may approach a harmonic speed that can get the shaft doing weird things.
That's why it is always better to increase diameter if possible. It increases stiffness as the increase in diameter cubed, IIRC.
R. 4" DOM shaft, 44" loooong, 1350 U-joints on both ends. Mid 10's and 7K through the lights. No problems.
Fastest 300
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Re: limits of stock driveshaft?
[Re: moparx]
#2156289
09/17/16 03:44 PM
09/17/16 03:44 PM
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Joined: Jun 2008
Posts: 10,847
Oakdale CT
gdonovan
I Live Here
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I Live Here
Joined: Jun 2008
Posts: 10,847
Oakdale CT
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my one buddy is constantly complaining about vibration problem on his brand "c" street car. he has had a couple of new shafts made by the local truck shaft shop, but no improvement.
Been there, done that. Max speed they balance at is 2000 rpm. I laughed at the guy when he told me he "high speed balanced it" and said are you aware how fast the shaft is spinning while jamming through the traps at the track? Try 6k+ Truck shops. pfft. That being said I pounds the crap out of my GTX with a stick, slicks and healthy 440 for hundreds of passes without failure, shaft is still in the car to this day. For a fairly mild car I'd not have a concern as long as the factory shaft is in good shape.
"I think its got a hemi"
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Re: limits of stock driveshaft?
[Re: gdonovan]
#2156317
09/17/16 04:50 PM
09/17/16 04:50 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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The shaft needs to be good for added torque, traction and rpm... those are the 3 major factors... the factory shaft isnt held to all the greatests tolerances but not bad.. if you have .010 run out you might feel it.. if its more you will.. diameter is strength along with the material.. I have had stock shafts be bad from the factory(just a small vibration).. I took it into work and took it to the lab that balances them.. it was bad and he balanced it and added weight to get it right... that big weight that hangs off the trans is there to change the frequency that the vibration was at to a point that is out of the normal shaft speed... I buy a new shaft for all my builds.. Dynotech is who I use for all of them.. never had any issues with there parts 
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Re: limits of stock driveshaft?
[Re: MR_P_BODY]
#2156355
09/17/16 06:05 PM
09/17/16 06:05 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
master
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master
Joined: Oct 2003
Posts: 7,506
Az
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The shaft needs to be good for added torque, traction and rpm... those are the 3 major factors... the factory shaft isnt held to all the greatests tolerances but not bad.. if you have .010 run out you might feel it.. if its more you will.. diameter is strength along with the material.. I have had stock shafts be bad from the factory(just a small vibration).. I took it into work and took it to the lab that balances them.. it was bad and he balanced it and added weight to get it right... that big weight that hangs off the trans is there to change the frequency that the vibration was at to a point that is out of the normal shaft speed... I buy a new shaft for all my builds.. Dynotech is who I use for all of them.. never had any issues with there parts >010" is a good rule of thumb on run out. More than that and you will feel it.
Fastest 300
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Re: limits of stock driveshaft?
[Re: dvw]
#2156452
09/17/16 09:23 PM
09/17/16 09:23 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I've measured lots of shafts. Know what the spec is. Never seen any below .030 "
Doug My Dynotech has .006 EDIT also if it has a minor vibration turn the shaft 180* on the diff yoke to see if it goes away or gets worse.. there is a test you can do with a aircraft clamp.. tighten a clamp on the shaft in the center... mark where the screw part is.. put 3 other marks on the shaft equally spaced(you have 4 marks now) try it at all 4 spots to see if it gets better or worse.. then if it changes(either better or worse) you will need to balance it
Last edited by MR_P_BODY; 09/17/16 09:44 PM.
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Make sure and use the good HD solid center U joints with no grease fittings on them 
One of the legal NHRA Stockers, 1971 demon 340 SB 904 ran 1.34 60 ft times with a stock shaft with HD U joints a bunch of times with the front wheels 2 to 3 ft off the ground on every launch 
