My 1970 12 bolt
 

Well thanks guys error fixed found a cou 331 open and it arrived home safe. I made a stupid mistake 15 years ago and put the 12 bolt in my 1972 formula. This new unit has very light pitting and it's date coded correct for my car. I will slowly start the restoration little at a time. I might have it just rebuilt open or should I go posi? That's brain storm number 1. 2nd is Changing axel ratio. This unit is black is that stock over spray.? Powder coat or paint? Please share pics . I've never done this before. Thanks
Is it OK to store like that on a cart?

From your second picture, I'd call that worse than "light pitting". It's going to require a lot of building primer and sanding to look smoother. I would think in dry Cal. you could find a better example to start with. My advice would be to keep shopping.

Well my guffy obsession with number matching date code stuff got me to buy it. I'll have it rebuilt and powder coated to preserve it. What's real different between posi and standard? I need a good lesson. Thanks

Tube thickness
 

Thanks . Do you know how thick the housing tubes are?

100% agree with Ric. To get that condition of axle housing/housing tubes to a housing with very clean axle tubes, you will be looking at a TON of hours/experienced labor. After the derusting process, an easy 20 hours of work. multiple coats of epoxy primer & high build primer & careful hand sanding . When done, ready for paint, the stamped codes on the tube most likely won't be legible. To solve that, all of the code will have to be over stamped with the correct font stamps (not an easy task to obtain them). Would be better off starting with a proper date window clean '70 F COS coded housing. Many more COS/3.07's out there. Then have the rear built with a high quality ring & pinion set, new Moser axles, & the carrier of your choice.

Once powder coated you won’t be seeing any stamping

Such a rust pitted housing will still have a ton of low spots, if all one does is thorough cleaning, burn off, then apply powder coat. Not a powder coat fan on these. 3 times I've examined what were freshly installed powder coated F-body rears that spun an axle tube. One, it happened on the street, the other 2 from first weekend at the track. Mid 12 sec cars at best. My own opinion, and that's all that it is, heating these leaf spring housings up in the coaters oven, has an effect on the factory plug welds. On two of those rears I warned the owners, their housing should be put in my line up bar first, & then the center hsg properly TIG welded to the axle tubes. Then & only then a trip with the hsg for their "buddy" deal at the coaters.

Well guess I bought junk. ****. I'll just have rebuilt and clean it up prime paint it. I never restored a car before and not taking it to the race track not driving it everyday . I'm sure the prime paint will fill in stamp code but I can document it for my daughter. It will be her car and just wanted all correct components. I regret putting my 12 bolt original in my 72 formula but oh well. Car came from Michigan so I am thinking it was pitted too. I have a clean cos but not correct dammit.

Powder coat
 

Is it possible to add welds to prevent axel from breaking original welds. Maybe I should have bought a brand new axel but I was told they only last a few years. This is a learning experience.

More pics
 

Here are more pics

Yep, that's a rough one. At least you can easily find a better cover to handle that part of the problem.
Hope you didn't pay big money for that one.

Welding the axle tubes to the center hsg on leaf spring rears has long been a tried and true practice to prevent an axle tube from spinning. Many years ago, i spent nearly a full day carefully cleaning up the appearance of a previous hack job of stick welding on the axle tubes of a '66 Nova 12 bolt housing. Ever since that mess, when I've needed to weld housing tubes to a center housing, I've loaded up the housing & my line up bar setup & drove to one of my local friends that are very handy with their TIG. End result is a beautiful small weld line, something that while not correct, I can at least stomach its appearance on a higher level restoration. As far as the "new" 12 bolts go, they are nowhere near correct appearance wise for a serious restoration build, As something to beat on, the Moser center housing is superior in strength to any of the factory 12 bolts, so if the purpose build of the car is the "hot rods to Hell" route, definitely an option.

My 12 bolt
 

My goal is to have matching correct components. Thanks for advice I do have a clean cos but not date code correct 331 cou. This one came from.Texas that sold with a ta. This is second ta I have seen with incorrect rear end. I'll probably end of having it rebuilt tape the stamp prime filler primer said then binding primer then single stage paint and call it good with a new cover. I'll remove tape on last coat not to hide my stamp. I knew it was pitted and I'm glad it made it home.

1970
 

Can anyone please tell me advantages and disadvantages of standard vs posi? And will a 307 kill performance. Also wondering if Transmission Pitts too?

307 is a good all around gear. Only really need a saft-t-Trac if you plan on racing really.
Your Esprit rear could be made to look exceptional, with correct date and code, in STEEL.
your driving needs should determine your gear. You said once you'll do highway, so 3.07 should fit that.
If you don't plan on burning your tires, or drag racing , you don't need a " posi".
But then people put forged pistons in ice cream getters...

The posi
 

My cowork said a standard spins either tire faster when turning and is a better on road it prevents Wipeouts. Is the limited slip the same? Or will you wipe out on country curvey roads. Yep I'm a little confused.

The saft-t-Trac applies power to both wheels equally while an open will apply power to the one with less traction.

Usually a good thing like when one tire is on ice and one is on dry pavement, the one on pavement will get power and move the car.
With an open rear the tire on the ice will spin like crazy and the car will not move.

The problem with the saft-t-Trac is when the tires are overpowered by HP the tires can't get any traction and both will spin, which then provides no control on the rear of the car. (the rear will go wherever it wants to)

With that gear it would be harder to break the tires lose than a steeper gear.

:)

With a "posi" rear, you do have to be prepared for the back end of the car to go sideways when the tires spin. I find it's not so bad in a straight line but in a turn it can get out of hand in an instant if your not prepared for it. Mashing the pedal in a turn is not a great idea. But, when I was a rambunctious youth, I liked driving sideways. It can be quite a lot of fun but that kind of thing is frowned on these days. Looking back it's hard to believe the stuff we got away with.

Nacho the COT axle in my car is about similar condition (pitting) as the COU you have. What is the whole date code on your tube? As I recall mine is 0415 G 1.

Date code
 

It looks like c o u 0115 G 2
What's the G 2 mean? Second shift I'm guessing
My car assembled 1st week of March to I think.its a good date