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Need some advise on my rear end. ;)

depends on if it's an 8" or 9", and what you have in your car.
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Right-a-mundo.

I read back through the thread and couldn't find anywhere that you stated which 31 spline Trac-loc center the guy is selling? Is he selling an 8" unit or a 9" unit?

Secondly, you need to determine exactly what size rearend housing you have before proceeding... 8" or 9" housing?

If you have an 8" housing and he's selling a 9" centersection, the deal is dead until you find an acceptable 9" housing.

To answer your question though, I'd have him make me a pair of 31 spline axles before I had him "down-grade" the center section from 31 to 28. A 9" rearend with 31 spline axles is about as tough as most would ever need.
 
It is a 9" he is selling. I will go tomorrow to my storage unit and check on mine... I'm almost positive it is a 9" I'll repost tomorrow and let u guys know. Thanks a ton. I'm hoping to make something happen with this thing./
 
If you knew what one looked like, looking at it would be the easiest way to ID one. But since you don't, take a 3/8 socket on a long extension. If you can't put the socket on the bottom third member nuts, it is a 9". If you can put the socket onto the nuts then it is a 8". Hope this helps.

I run a 9" with the limited slip and love it. If you want to drive on the hwy a lot, 3.50's would be a good choice. This ratio will give you great seat of the pants feel and good cruising options with you stroker.
 
Yeah this is really sounding like the setup I'm after. Like I said I'm almost 100% positive i have a 9 inch, but will post tomorrow from my storage unit when I know for sure.
 
Well, crap.

I believe I have an 8". Here's a couple photos for verification.

img3608rk4.jpg


img3611vt7.jpg


img3612gx8.jpg


img3613px1.jpg


img3607vj8.jpg



Sigh. So if I am to do this swap I need what?

New 3rd Member
New 9" Housing
31 Spline Axles
Anything else?

Thanks guys.
 
OK.

I just found a guy with a 9" from a 67. That should be the same length as a 70, correct? He said it is a posi, is 28 spline, hes about 30 mins from me, but doesn't know the gearing. Here's the ad

http://detroit.craigslist.org/pts/784762334.html

Let's say I can get it for $400...

Is there a way for me to have him fgure out the gearing without mounting tires and doing it by spinning the 3rd member?

How hard is it to change the gears? Keep in mind I am a fool with rear ends, but not completely mechanically retarded...

He sad he'll do whatever he needs to do to figure out the gears, but just doesn't know the easiest way.

Thanks again.
 
Since the center section is removed, the easiest way to determine the gear ratio (if it's not written on the side of the ring gear) is to divide the number of pinion gear teeth into the number of ring gear teeth.
 
Ok, wait...

so take the number of pinion gear teeth, and divide that by the number of ring gear teeth? Is that what you're saying?

Will it come out to something like "3.25" or will it be like "3.24987" kind of thing? Just so I can tell him what to expect.
 
How hard is it to change the gears?
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It's not hard, it just takes a little bit (or a lot) of patience setting up the backlash on the gears. It's not something I'd recommend to do by yourself the first time.

Also.... with the pinion yoke pictured on that center section, it's unlikely that unit came out of a '67 Mustang.... The rearend housing may have, but probably not the center section. The pinion yoke pictured would likely have to be changed in order to connect to your existing driveshaft.

You'd still need a 9" brake setup....

You may want to keep looking around.... patience is key to success... the perfect setup will come along, just keep looking.
 
Yes, but you typed it backwards....

"divide the number of pinion gear teeth into the number of ring gear teeth"

The pinion gear will have like 9 or so teeth on it..... the ring gear will have 32 or so....

32 divided by 9 = 3.55555555 For a ratio of 3.55:1

Capish?
 
Ok thanks a ton! He counted and it is 44 teeth on the ring gear and 16 on the pinion. so it is 2.75 gearing. Think I'm going to pass.

Thanks, I'll make sure to update wth whatever one I find next. Sigh.
 
Gearsets aren't exactly difficult to change if you know what you're doing, but setup is very picky. It requires special tools and knowledge, and it's easy to screw up the gears if you don't know what you're doing. Usually I recommend letting a shop do it, especially since some of the proper tools are expensive and sometimes hard to come by (dial-type in-lb torque wrench, pinion yoke wrench, spanner wrench, dial indicator).
 
Ok the guy originally talked with with the 3.50 and 31 spline said hes 99% positive he has a 9" housing with axle tubes in his shop. He wants me to measure mine and email the measurements to him so he can check monday morning. if he DOES have it, he said he'll set it all up (3rd member, 31 spline custom length axles, housing) for me real cheap because its helping get this shit out of his shop...


What measurements do you recommend I provide him? Flange to flange? or like where it attaches to the leaf springs? anything else?

Thanks guys... I'm really hoping to work this out.
 
All of the above. Worst case, you can get the spring perches cut and re-welded, but the housing needs to be the right width.
 
He mentioned a measurement that would require me to remove the axles? I'd prefer not to do this... Any idea what he was looking for?
 
Ok, guy quoted me $1100 for a complete bolt in 9".

Thats a Posi 3.50 gear, 31 spline axles custom cut, correct housing, and brand new drums. Everything I'd need, I guess.

$1100 sounds fairly reasonable, but I can't afford it. So I asked if he was willing to trade. I offered him my 8", an additional 8" from another 70 (guy has it on craigslist for $75) and some cash.

He said both 8s and $650 and he'd do it.

Sound fair?
 
He said both 8s and $650 and he'd do it.

Sound fair?
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When I swap 8" rears for 9" rears, I get tired of tripping over the 8" rearends and eventually give them away to the first person who shows up. Personally, I place no value on an 8" rearend, so your deal of $650 for a bolt in 31 spline tracloc drum to drum 9" rearend looks pretty good to me.

If you make the deal..... when you're loading up the new 9" into your truck and right before you hand him the cash, ask him if he's going to stand behind the unit? That way if the gears start howling, you'll have someone to adjust/fix them.
 
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