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Discussion Starter #1
Alrighty, I actually have a question! :)

My cat currently has a 3.00 open pig in the rear end (yeah, yeah, I'm just getting around to the rear end of the car)...

I need to switch it to a posi unit. What I wanna know is if I can just pick up a late 60's early 70's 9" posi pig and shove 'er in there with no problems (Provided the spline count matches)...

The other option I guess would be to replace the spiders with a Powertrax unit?

Comments? Opinions? Free posi rear-ends?
 

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Logan,
This is a simple swap. I have done it a few times and never had any problems. The best way is to find a unit from a mustang, cougar or midsize car. You can use a pick up unit but must swap the yoke as it is deferent. I'm not sure about big car units but with that you need to look out for the 9 3/8" units. Neal:alien:
 

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Contributing Sr Motorhead
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Posi rear pig

Logan,

I've got a couple spare posi pigs laying around. I'll trade you some rust-free Texas quarterpanels for my 73s for whatever ratio posi you want! ;) Just load those puppies into that truck of yours and make the trek to Columbus the first part of next month for the All-Ford extravaganza and we'll do the deed! ;) ;) ;) I've got 2.75, 3.00, 3.25, 3.50 3.70 and 3.91 units laying around.... The 3.50 set is the only 31-spline posi I've got right now, the rest are all 28s.

In all seriousness, putting a posi in is very easy. I'd suggest that you have the posi clutches replaced before you install it in the car though. Nothing worse than going through all that nasty, smelly work to find out that the posi is wasted. There's nothing worse smelling than the stench of old posi rear end lube. I try to minimize my exposure to that stuff if at all posible.

The problem with replacing the clutches is that you have to separate the halves of the posi unit to do it, and that means taking the ring gear off. Then you'll need to reset the pattern and backlash when you're done.
 

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Discussion Starter #5
I could probably sneak onto Ken McDowell's place with an air chisel and get ya some quarters... :) He'd never notice... heheh

I've got a bid on a decent 31spline pig on ebay right now, we'll see how it goes... Failing that, I'll be beating on your door to send me one of your pigs.

Drive to columbus in my lightning...that's funny... I get like 10mpg in the damn thing...

Nowadays, the pregnant wife won't let me out of her sight... I have to get the remaining work done on my cat before the twins show up in July... Something tells me my parts fund will be redirected arbitrarily to the diaper fund. :rolleyes:
 

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Logan's Columbus trip

Lightning only getting ten MPG? Gee, I'd get rid of that pig if I were you....you're gonna need the diaper money! Even the Wife's F-250HD with its 460, automatic and 4.10 gears gets 11-12. Loaded or empty, city or highway, it doesn't matter!

E-bay for a posi? Are you nuts? The shipping alone will kill you!Couldn't you find a friendly junkyard in your area that will cut you a deal on a posi rear? I get all the 9" posi pigs I want for $75 a piece at my local yard.

I hope I can get out of work to go to Columbus this year. Having to work on Saturdays sucks! I gave up drag racing fifteen years ago too because I couldn't make it to the track in time, not to mention my reaction times went into the toilet being up for some 20+ hours! Found a guy on my mail route with an attic full of old Mustang parts he's throwing away!. How 'bout a disc brake setup for a 66? Four-piston calipers, spindles, steering linkage, quick ratio manual steering box.... Those parts found their way into the trunk of my car real fast! Trading material?

By the way, congrats on the twins! There goes all of that discretionary income. No more money for (adult) playtoys for a while. My wife and I spent tens of thousands trying to have kids - fertility drugs, in vitros, etc. Nothing to show for it but a depleted bank account.
 

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Discussion Starter #7
The lightnings fuel mileage might have something to do with the extra 120hp, 100ft/lbs over stock... :D, Runs a clean 12.6 at 109 in the quarter... Not bad for 4700lbs eh?

As for the pumpkin, I already got out-bid (What can I say, I'm cheap)...

Now I guess I'll call around the local yards...This oughta be fun.

Ugh.

Yeah, our kids are invitro babies... We got lucky on the first cycle, mind you, 3.5 years is long enough to wait. You're right, the lightning is probably going away (Wife wants a minivan)... I get to keep my cougar and drive her 98 Taurus...
 

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ok, just out of curiosity, how do i ID a posi unit at the yard?? my car has an open diff as well so it would help to come across one and slap it in. there are about a billion cars at the local yard with 9 inch rears, and im sure at least a few have a posi in them. BTW my car is only a standard coupe, so im preetty sure that it only has 28 spline axles in it. correct me if im wrong
 

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I got my trac loc from a bone yard, it was a 3:23 econoline van model. I already had the 3:73's so I put it together and there ya go el cheapo posi!!! I know exactly what you mean about kids and daddy's toys conflicting. BTW Logan, be carefull with those car seats in that cougar, thats the reason my headliner got ripped. It seems as though when you first have your kids you are broke constantly, diapers, formula,.ect... then you kind of even out for a while. I'm trying to prepare for teenage yours to come, I have 2 girls 9 & 10 and I can see some headaches on the horizon.
Good Luck
John
 

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Posi ID

I usually don't bother with trying to read door tags on the cars and trucks. Too much chance of having either the door changed, the sticker painted over, or whatever. Trucks and vans have a different coding system that I've never been able to figure out!

OK, one of the pig mounting studs will have a metal tag on it that describes everything you need to know about what the rear end is.

The tag will have two lines of characters stamped into it. The most important line is the bottom line. Starting at the left, where the nut holds the tag down, is the ratio. 3.00 would indicate a 3.00 open rear. 3L00 indicates 3.00 posi. The next character would be the rearend size. 8 indicates 8", and 9 indicates 9". Easy, eh?

On cars up here in the northern rustbelt climates, the tag will be very rusty and hard to read. DO NOT bend the tag off so you can look at it in better light out in the open. Chances are it will brrreak right through one of the first characters. I use a small knife to scrape the tag lettering to make it easier to read. It also helps to carry a mirror and a small flashlight.

I do most of my scrounging on the rear end 'pile' that the yard has. Much easier than trying to shimmy under cars in the mud, and much safer than crawling under there with a bumper jack holding the car.

Happy scrounging!
 

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Discussion Starter #11
I just got through calling NINE different ford specialty salvage yards around Dallas/Fort Worth and not one of them has any posi-pigs...

WTF?!

Dang nab it!!!
 

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junkyards and posi pigs

Logan, Geeeze, I fid that hard to believe that not one of those yards has any posi rears laying around. :rolleyes:

Most yards around here will give you the same line, too. They just don't want to bother checking. It is up to you to do the scrounging. And when you do, and you do find a posi rear, don't tell them it is a posi rear. Just simply say 'I want the rear end out of that blue Econoline or brown Country Squire wagon in the second row, halfway back'. Then they'll say, OK. and cut it out for you. Get it 'drum to drum' like you're gonna use it for your old Econoline or whatever. Same thing if you look through the rear end pile. Just grab the whole thing and take the posi pig off later when you get home and throw away the rest. Then if you're a good repeat customer, they will cut you a break on the price. This is just what I have found from experience in dealing with junkyards.

Happy hunting!
 

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Discussion Starter #13
Yeah, I think I figured it out, I either confused them by asking for a 9inch posi diff, or they were too lazy to look.

Soooooooooooooooo, I'm going to try a different tack. I'm going to ask for a "Late 70's Ford pick differential" and if they have any, I'll head down and pick through their selection. If I can't find a posi-pig, I'll pick up a powertrax locker conversion for an open diff.

Fortunately, there's an area of town that has 4 or 5 ford yards within a few miles of one another.

First off though, there's a swap meet this weekend, so I'll head out early Saturday and see if I can find one there reasonably priced...
 
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