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Discussion Starter · #1 ·
I originally built by car for street performance with the intent of
occasional runs at the drag strip.

Well, after my first few visits to the track, I think my occasional
runs are more like frequent runs.

I've only run street tires so far, but I plan a getting slicks for next
season. I don't plan on 5K RPM clutch dumps, but need better 60 foot times
and thus enough rubber to hook up better.

I have a 347 stroker, AFR 165 heads, cam is equivalent to Edlebrock Performer
RPM, Edelbrock Perfromer intake, Holley 650, MSD ignition, headers.

I've just replaced the C4 with a T5z and I have the original 8 inch rear
which I've just had rebuilt 2 years ago with a traction lock and 3.40
gears.

What I'm wondering, if I consistantly run with 3K launches with the
drive train last or am I one run from a new rear or tranny?
 

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I had a 66 mustang. 351w, T-5 tranny. The engine was never tuned right, and made around 280 rear wheel torque. It ran fine like this for years. The day I put on drag radials, the 8 inch straight up blew up. Shot out the drive shaft with pinion attached.

Then again, the 67 and up 8-inches are stronger than the 66 and prior units. Chirag on here has a 67 mustang with an 8 inch and it is still running great.

Chris
 

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What car? How heavy?

My car ('65 fastback 'stang) has a T5z and 8 inch (doesn't have the extra ribbing). Everything has held up fine until I started running slicks. The rear is making a whining noise now. Still runs fine. Just doesn't sound happy. I would launch it pretty easy and only pushed it to 1.83-4 ish 60 ft times. I also only have a 289. I have no reason to believe the tranny is anywhere near it's limits. I do believe the rear is. Got a real nice 9" sitting in the garage waiting for me to put it in.
 

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Discussion Starter · #4 ·
Its a 68 Mustang coupe. Don't know the weight. But the heads, intake, water pump are aluminium. And of course the T5z is lighter than the original C4.

I haven't had it dyno'd, but my engine builder thinks about 385 HP; I presume he meant at the flywheel.

I've made about a hundred passes so far and the rear is still fine. I've been running at an 1/8 mile track. My best is a 8.787 at 86 mph with a 2.139 60 foot time.

I do believe I damaged my T5z when I went from 1-2 sloppily and heard a "snap" of some kind, but that was me and not the HP. But the tranny still fine, although it tends to want to stick in 3rd once and a while.
 

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I'm running 1.57 to 1.59 60 foot times on my 8 inch with the factory 4lug axles... I wonder if the axle breaks first or I start breaking wheel studs?
 

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On 2006-10-25 15:30, Matt wrote:
I'm running 1.57 to 1.59 60 foot times on my 8 inch with the factory 4lug axles... I wonder if the axle breaks first or I start breaking wheel studs?
If you're running an auto tranny it will be much easier on the rear.

The '67 project car on this site ran a 8" for awhile. I think it eventually twisted an axle. Believe they replace it with a stronger aftermarket 28 spline piece. Don't know if they still run that 8" or not. They had a manual trans and some good 60 ft's on the way to 11 second passes.
 

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If it was me... I'd swap in a 9-inch.
Im running 1.68 60-foots and 11.65 and Im a little nervous with my 28 spline axles in a granada 9-inch rear.
If it does break... lets hope its in the burn out box or launch... Cause if there's one nasty event at a drag race, its when an axle goes at half track.
 

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Heres the run down on fordmuscle's experiance on the 8" at the drags in their high 11 sec 67 mustang.
Good luck
http://www.fordmuscle.com/archives/2003/03/project67/index.shtml

_________________
71 Pinto Sedan

5.0 block,B303,1.7 Rockers,beehives,'68 ported heads,Coated custom Must II headers,Edlb Airgap,Holley570,Msd Billet,Crane HI 6,Milodon 8 quart Deep Pan,2.5" 40 Flowmasters.

<font size=-1>[ This Message was edited by: 71hotrodpinto on 10/26/06 8:55am ]</font>
 

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I agree that a auto will be easier on parts, last time out two of the bow tie boys in our group lost axles running 8.40, and 7.90s in the 1/8 both with autos... I still think that the 8 is an pretty good rear end. Maybe I'm pushing the limits with factory stuff, judge for yourselves... I've got some shakedown runs taped http://video.yahoo.com/video/play?vid=996fe4b631e4e065be94eaa3904aca22.1022209

sorry about the crappy video quality. The reason I don't wanna switch to a 9 is the weight issue, they are lots heavier than than an 8. I'd like to know how ford muscle's car is doing with the aftermarket axles? Maybe it would be easier to go that route than a complete rear end swap.
 

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Discussion Starter · #10 ·
Yea, I've read the article on the 67 on this site. However, they're running
a lot quicker than I am and they we're doing 5K dumps of the clutch before
they broke it. That's why I was wondering if I'd get away with it.

And as Thordane65 mentioned, a 9-inch would be the way to go. But they
are heavier and I've heard that they actually loose more HP (less efficient)
than the 8-inch.

I do plan to go to the 9-inch someday, but with all the money I've spent on the
car in the last 2 years and all the money I'm now spending racing I need to put
that expenditure off for a while.

Nodoby's mentioned the how well they think the T5z will hold up?
 

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I have seen that 11 second Ford Muscle article and based on that and other info out there, it appears 8 inch with good axle shafts can easily handle up to 400 horsepower.
 

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It is important to note that that is with the later 8". It has extra ribbing which makes it stronger.

Yes, the nine inch I have is a ton heavier. I've removed and installed an 8" on my own years ago when I wasn't as strong as I am now. I need help with the 9" dry when I try and move it around the garage!
 

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The 8-inch is a good solid rear-end... but theres a reason why the factory left them in non-performance versions and went to the 9-inch.

Its not a question of WILL it break... its a question of WHEN it will break.

The guy is not running a mild 289... he's running an AFR headed 347!

Slicks are the killer for a rear end. Ive had 3 buddies drop thier rear-ends at the track the very first time out with slicks from street tires.
You might get lucky, but you've also got gobs of torque.
Good luck!
 

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366 stroker, runs on methanol, dial 6.60s in the 1/8 at 100+, runs two short 28 spline axles in the rear. He did lose one this year, but it obviously had a fault of some sort - it did not "break", it "tore" part way down the length. Took most of the year for it to fail too. He runs an auto - a stick will break lots of things if you're not careful with it.

You can also ask econodrag about running an 8" - he did it for years, running very fast, wheels up every pass. 8" is a fine part. If you can't drive your stick, you'll tear up a 9" too.
_________________

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70 Mustang 302 / 06 Ranger, 04 SuperCrew parts hauler
http://raceabilene.com/kelly/hotrod



<font size=-1>[ This Message was edited by: ckelly on 10/27/06 2:48am ]</font>
 

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On 2006-10-26 10:21, 67VertMustang wrote:
I have seen that 11 second Ford Muscle article and based on that and other info out there, it appears 8 inch with good axle shafts can easily handle up to 400 horsepower.
The key to this car is the year. 67 and up are okay to that power level. 66 and below are not.
 

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9 inches are not that much heavier, the housings and axles are about the same weight, the extra weight is in the center sections. I remember weighing the 8 inch to be around 55-60 pounds and the 9 inch was close to 80 pounds.

So at max probably 30lbs more, not that big of a deal when you consider how much stronger it is.
 

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Discussion Starter · #17 ·
Lot's of really great info here; thanks guys!

However, I'm still not sure I have a good feel for what to do since there are opinions and examples on both sides of the issue.

I suppose the best thing is just to continue to run it until it breaks, then go out and get a 9-inch.

By the way, still no comments on how my T5z will hold up; I'm more nervous about breaking that....
 

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On 2006-10-26 12:30, mikemustang289 wrote:
9 inches are not that much heavier, the housings and axles are about the same weight, the extra weight is in the center sections. I remember weighing the 8 inch to be around 55-60 pounds and the 9 inch was close to 80 pounds.

So at max probably 30lbs more, not that big of a deal when you consider how much stronger it is.
I should mention that my 9" really has nothing from ford making it up. Decided to go heavy duty aftermarket. It weighs a ton (more like an extra 100lbs) but should hold up to whatever I want to throw at it.

You will get as varying responses to the T5z as the 8" rear. The one on the 331 powered mid to high 11 second '67 stang project car here has held up with slicks. Guess what? It's only a regular world class without the "z" upgrades. Others will break them in a 13 sec car with drag radials. Speed shifting and your driving style will most likely determine it's life span. Some get them to run forever in pretty quick cars and others break them in slow cars in the first few passes.


<font size=-1>[ This Message was edited by: 289nate on 10/27/06 6:00am ]</font>
 

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[/quote]

I should mention that my 9" really has nothing from ford making it up. Decided to go heavy duty aftermarket. It weighs a ton (more like an extra 100lbs) but should hold up to whatever I want to throw at it.

You will get as varying responses to the T5z as the 8" rear. The one on the 331 powered mid to high 11 second '67 stang project car here has held up with slicks. Guess what? It's only a regular world class without the "z" upgrades. Others will break them in a 13 sec car with drag radials. Speed shifting and your driving style will most likely determine it's life span. Some get them to run forever in pretty quick cars and others break them in slow cars in the first few passes.


<font size=-1>[ This Message was edited by: 289nate on 10/27/06 6:00am ]</font>
[/quote]

What kind of housing did you go with? Aside from my stock housing, the rest is aftermarket, and the weight difference I am talking about is with a Nodular case/Locker compared to a stock ribbed 8 inch case with posi



The housings were nearly identical in weight, not sure about the axles since I didn't weight them, but I know for a fact that the 9 inch pumpkin was under 80 pounds and when I shipped the 8 inch pumpkin it was close to 55lbs.

That's 25 pounds, I don't see how you can manage to tack on another 75 pounds unless the housing is made of some type of thick are armor plating.
 

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Here are some of the component weights from Ultrastang (He has lots of 9" info-just poke around on his site)----> http://www.ultrastang.com

FORD REAR END WEIGHT COMPARISON 8

8-inch Rear End Assembly Weight : 170 lbs.

1. Housing: 36 lbs.

2. Axles: Medium Journal, 28-spline -15 lbs. ea.

3. Brakes: Small 10" x 1¾" Drum Assemblies - 22 lbs. ea.

4. 3rd Member: Reinforced Revision 8-inch Case - 60 lbs.




9-inch Rear End Assembly Weight: 194 lbs.

1. Housing: 38 lbs.

2. Axles: Large Journal, 28-spline - 18 Lbs. ea.

3. Brakes: Massive 11-1/32 x 2½" Drum Assemblies - 26 lbs. ea.

4. 3rd Member: Conventional Diff. - 68 lbs.
a. w/Traction-Lok Diff. - 71 lbs.

(24 lbs. Difference Between Drum Brake 8" & Drum Brake 9" Rear End Assembly).




Versailles Disc Brake Rear End Assembly Weight: 215 lbs.

1. Housing: 39 lbs.

2. Caliper: w/Pads, Anchor Plate & Flexible Brake Hose - 24 lbs. ea.

3. Axles: 20 lbs. ea.

4. Rotors: 10 lbs. ea.

5. 3rd member: Conventional Diff. - 68 lbs.

(45 lbs. Difference Between Drum Brake 8" & Disc Brake 9" Versailles).




Wheel/Tire Comparison:

1. Stock '66 Mustang GT Styled Steel Wheel w/ P195/70R-14 Tire - 46 lbs. ea.

2. Weld Draglite Forged Aluminum Wheel (15" x 8"
w/ P245/60-15 Tire - 38 lbs. ea.




Miscellaneous:

1. 8" Drum Brake Assembly: (10" x 1¾" Drums): 22 lbs. ea.

2. 9" Drum Brake Assembly (11-1/32" x 2½" Drums): 26 lbs. ea.

3. Lincoln Versailles Disc Brake Assembly: (10½" Rotors) 30 lbs. ea.

4. Lincoln Mk VII Rear Disc Brake Rotor/Caliper Assembly Weight: (11¼" Rotors) 22 lbs.ea.

5. Ford Explorer Rear Disc Brake Rotor/Caliper Assembly Weight: (11¼" Rotors) 25 lbs. ea.

_________________
Dennis

65' STANG, 3160 lbs

393W NA, 2.78 Toploader 4 Spd, 9" 3:70 Posi
Pro Comp Heads, Vic Jr. Intake, 750dp, 236/561 Solid Cam, 9.6CR, 1 3/4" Headers, Lakewood, Subframes, Caltracs



<font size=-1>[ This Message was edited by: dennis111 on 10/27/06 8:05pm ]</font>
 
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