[BAR396]

Trading my 4X4 truck for a 12 bolt with multi-leaf springs. Contemplating modding it and installing it in my 68 project Camaro. Providing it isn't a BE rear or date coded for someone needing it for resto.

Would getting the axle tubes welded and some type of c-clip elimination be a start? It will be primarily a track car with a 396/th400. Aside from aftermarket axles, any other tips for strength/dependability?

thanks
Brett in Boise

[Everett#2390]

Your suggestions would be a start.
Adding to the list: studs for the caps, maybe steel caps and have it aligned bored.
Girdle cover along with a brace. www.lpwracing.com
Trianglate the perches to the tubes, in fact, go from the extreme end to up & over the tube to the other end of the perch, as in one piece of steel, if leaf spring route is taken. People have done it with two plates, but the top welds of each plate welded to the tube gets pulled and the tubing cracks.
Lighten gear.
Spool, if not driven on the street.
Eaton carrier.

Or, get a 12-bolt design 9 inch axle from aftermarket.
Maybe big gear head will chime in with suggestions.

[pink panther]

i hear those c clips leak i'am gonna use ford ends on my 12 bolt i don't anything leaking on my 12 bolt

[ProdigyCustoms]

Well, we sell a LOT of Moser, In fact we got a call yesterday from Moser letting us know we were deep in the top 10 in Moser sales. I tell you this because we deal with these decisions with customers everyday. What we find is that if someone has a original dated Camaro 12 bolt and want to beef it up. It is always better to sell the rear to a person needing it for a proper restoration. This way you help someone else preserve history and you don't massacre a rare piece. Also dollars wise (most important) works out better in the end to sell and order a new stronger rear.



A original 12 bolt open rear with 3.07, 3.31 gears, etc., is normally worth $1000 to $1200. A dated, coded posi, 3.55, 3.73 etc. is worth $1700 to $2500.



Either way, regardless of which you have. To build that original rear into a killer rear is going to cost at least to cost of a new rear or more.



We can do Camaro 30 spline 12 bolts, with new stronger then original housings, ring welded tubes, big ford ends, stronger axles, sock or narrowed to you width (no extra charge), on your door step for a tick more then $2000.



Want a real baddass rear, add $300 and do a 33 spline Tru Track and Performance cover and have the baddest 12 bolt good for 700HP.



If you try to build your open rear equal to the new rear, it will cost more.



Here are some round numbers for you:



Posi chunk $350+ Depending on what you choose
Gears $200
Install kit $125
Big Ford End $80
Axles and bearing $425
1350 yoke $50
labor to weld ends, assemble rear $350



Quick math, about $1500



And in the end you ruined a original rear someone else could use.

[Wooderson]

Originally Posted by ProdigyCustoms

A original 12 bolt open rear with 3.07, 3.31 gears, etc., is normally worth $1000 to $1200. A dated, coded posi, 3.55, 3.73 etc. is worth $1700 to $2500.

Would you say these estimates are for just '67 to '69 units, or do they include the '70 to '72 12 bolts? From what I've read, the '70 to '72 units were made in far fewer numbers.

[big gear head]

If you want all of those modifications then I'd recommend getting a new Moser 12 bolt to start with. It will be much stronger and you can get it built exactly the way you want it wothout having to modify it yourself. Save the original Chevy 12 bolt for someone who needs it for a restoration or street car.

If you are set on modifying this one then can I recommend these?
http://www.camaros.net/classifieds/s...ct=31096&cat=8

[Moonpie]

Adding to what Wooderson asked, How would one determine if the gears in the 12 bolt I have are factory or aftermarket? They are supposed to be 4.11's but I have never checked them. The rear isn't installed and would be when the time comes in my resto. It's a 12 bolt posi unit. What you say makes real good sense about saving a rearend.

[big gear head]

The GM ring gears are marked GM and have a GM part number on them, along with the date. If you have factory installed 4.11 gears then you will also have a 4 series Eaton posi. The housing will also have the 4.11 posi code stamped into the axle tube.

'70 was the last year for the 12 bolt in a Camaro, but the price for them isn't as high as the '67 to '69 12 bolt.

[ProdigyCustoms]

You need to find the axle code for the rear which is located on the front of the passenger side tube about halfway between the center section and the tube end. It will be stamped (imprinted) with a set ot letters / numbers. This is the date the axle assembly was assembled and the code for the gear ratio and posi / no posi.

Something like BV0512 E which would break down as

BV = 4.10 Posi
0512 = May 12th (year to be decided by casting date)
E = Eaton

Since 68 and 69 are both multi leaf and both use the same codes, you have to get the casting date to determine what year the axle is for.

To dtermine the year find the casting date which is cast (raised letters) into the center section. There are 4 triangle webs in the four corners around the differential cover.

In on of those will be the casting date for the center section which will read something like

D 30 9 which equals

d = April
30 = 30th day of month
8 = year of casting.

This date will proceded the stamp date as the center had to be cast so the rear could be assembled.

Also, of great importantance. Rear ends cast AFTER the 7th month of a given year, are the following year component since new model year production starts in August 1 or so. So a rear cast G 30 8 is August 30 68 is actually a 69 correct rear.

67 rears are the same deal but are mono leaf and will have a traction bar mount on the right axle tube.

[ProdigyCustoms]

As freddie mentioned the 2nd gen 12 bolts are rarer. Somoen with a 70 Z28 that needs that rear could really pay up for a date / coded original 3.73 rear.

[DOUG G]

I got a 12 bolt from a friend out of a 68 Nova. Someone left the cover off and it was rusted inside and out. After a good cleaning and painting I added c-clip eliminators (moser),35 spline axles (Moser),4.10 gears,spool (moser),and a TA support cover. Good for 8's or better (so I'm told) and I should never break it
I have about $700 for parts in it.

[Wooderson]

Thanks for the info. I have a 70 3.07 non posi from an SS 350 car. I thought about when I finally clean it up and sell it, I will leave it unassembled because I'm figuring most guys probably aren't looking for a 3.07 rear. ( This is not a for sale ad. It'll be a while before I get around to it ).

[BAR396]

Thanks guys. From what I was told it codes out to a 3.08 gear, unsure if it is an open or posi. Sounds like Frank needs to hook me up and I may have to find someone who needs this for a resto. Hey Frank I have an old VHS tape with some footage of a Camaro show with someone doing some judging. Is my memory incorrect or was that you?

Thanks
Brett in Boise

[ProdigyCustoms]

That is not me, that is a guy with a mullet, and I would NEVER do that!

Yeah, it is probably me 15 years ago or so when I was thinner and had lots of hair!

[69 z11]

Does anyone here know who does 12 bolt rebuilds and gear setups in Colorado? Got a posi and 3.73's coming for mine and would just like to pull it out and drop it off if there is somewhere nearby.