I tried a search through the archives and could not come up with an exact measurement for a '65-'67 12 bolt from drum face to drum face (in other words, overall as installed width, not just to the backing plates). Several posts had conflicting widths on backing plate to backing plate measurements.

Would anybody with one of these rear ends be kind enough to provide an exact mesurement? Thanks http://www.chevelles.com/forum/smile.gif

Take a look at this web site.
www.angelfire.com/tx/lonestarclassics/abodyinterchange.html (http://www.angelfire.com/tx/lonestarclassics/abodyinterchange.html)

Don't how to create a link here yet, but the info is there.

68ElCamino
T.C. #413

Thanks for the link! Lot's of good data!

Only problem here though is that the data on page http://www.angelfire.com/tx/lonestarclassics/chassis.html is incorrect for the '68-'72 rear end width (which means that it is also incorrect for the '64-'67!!!). I have a 12 bolt out of a '72 El Camino and "axle face to axle face" (no drums installed) the measurements are 60 5/8". Adding drums to this increases the width 3/32" per side (thickness of brake drum face) for an overall installed measurement "drum face to drum face" of 60 13/16" http://www.chevelles.com/forum/confused.gif

Again, could someone please actually measure their actual pre '68 12 bolt so that we can also get the above reference page corrected too? Thanks http://www.chevelles.com/forum/smile.gif

I thought the info was correct the first time I looked at it, but now I don't think so. My housing in out tof the car, I will get off my dead ass and measure it. I can give you the distance between the backing plates, the tires are still on the beast.
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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette

[This message has been edited by Wally (edited 01-16-2000).]

OK, it's about 53 1/2 inches between the backing plates. You should be able to compute the overall by using the rear you have and measure the distance from the backing plate to the face of the axle. If I had the tires off the rear I could be more precise.

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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette

I just measured a 65 10 bolt and it is 58 3/4" axle flange to axle flange I don't have drums on it.
Wouldn't the 10 and 12 bolt be the same width?
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Philip Valentine
Gold Member #42
"Perseverance is not a long race; it is many short races one after another."
philip@chevelles.com



[This message has been edited by 64elcamino (edited 01-16-2000).]

Wally & 64elcamino, thanks for the feedback. I would like to think the 10 bolt is the same width as the 12 bolt but I guess we'll find out once and for all http://www.chevelles.com/forum/smile.gif

Per the numbers on my axle tube, I have a 67 12 bolt posi rear. My measurements with the tires off are 55.0, inside of backing plate to backing plate, and 61.0 drum to drum.
The 67 posi has been documented.

Duane, thanks for checking, however, the rear end I am using as my reference point is a 1972 El Camino 12 bolt 2.73 non-posi from a factory matching number car. It's backing plate to backing plate measurements are 54.5" http://www.chevelles.com/forum/confused.gif which as I mentioned, with drums installed, equates to 60 13/16" overall width. Somethng doesn't add up http://www.chevelles.com/forum/confused.gif I know that the '68-'72 Chevelle, El Camino & Monte Carlo share the same rear end housings. Hmmmmmm. I need more help!

The 64-66 is (I believe) 1" narrower. But the 67 is the same width as the 68-72. Just thought I'd help clear up some misconceptions...

FWIW, http://www.chevelles.com/forum/smile.gif
CBTN lists the following: (all dimensions are from axle tube flange to axle tube flange and a 10 bolt length is same as 12 bolt lenght)
65-69 Passenger: 58 1/4"
68-69 Nova: 54 1/4" Leaf rear
65-67 Chevelle: 54 1/4"
68-69 Chevelle: 55 1/4"
67-69 Camaro: 54 1/4" Leaf rear
Thanks again Mr. Colvin http://www.chevelles.com/forum/biggrin.gif

With prices of the 65-67 continuing to go up, http://www.chevelles.com/forum/eek.gif in the long run it may be just as cost effective to get a 67-69 rear and cut the leaf mounts off and weld on the correct mounts for the upper and lower control arms and springs.

Just a thought.


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AJ67SS
67 Chevelle SS Conv
69 Camaro RS

NO way will you find a 67-69 camaro 12 bolt rear to make that kind of mod to..those 12 bolt prices went up way before the chevelle ones did. My last one with 3:31 gears and posi sold for $500 in a heartbeat with a list of guys who wanted it next. I was told it was now up to $800 for one of these used rears..IMO the 68-72 rear works fine in a 66-67, but the 64-5 will need the earlier rears because of the fender skirted design of the quarters.

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

Ok here goes nothing...

I have what I belive to be a 1967 12 bolt rearend.
Code is CD7E21OB on Passsenger side axle tube on the inside (driveshaft) side of the carrier. CD is posi 3.07, 7E21 = May 21 1967, O is not known and B = Buffalo Gear.

It has a flat mounting surface for the coil spring with a hole drilled through. It's measurements are 54.5 inches backing plate to backing plate and 60.5 inches Drum to Drum.

Exactly what the '72 El Camino measured.

Can some one measure their 70-72 12 bolt posi rear and confirm these widths?

It's got me confused! Thanks,

--Andy--

I just re-read all the posts. This is confusing as all heck!
It appears that the CBTN and www.Angelfire (http://www.Angelfire) web site lists are wrong. Wally's & 64 ElCamino's measurements appear to be about the same (1964-1966) 59" +/-, while JMB's, Duane's and my measurements (1967-1972) are about the same 60" +/-.

This supports the theory that the 64-66 cars are 1 inch narrower.

1967 appears to be the same width as 1968-1972 but some might have the flat saddle spring mount of the 1964-1966 cars which explains my set-up

Do we agree or am I all wet?

--Andy--

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1970 Chevelle SS Convertible
1937 Master Business Coupe
1996 S-10 Blazer
TC #551, ACES #3513
VCCA #35642
Yup, I'm Chevy Prejudiced!!!!

[This message has been edited by AndyP (edited 01-18-2000).]

with the flat plate mount for the spring, I would think that is a 66 rear..66 used a metal piece to secure the spring to the rear with a bolt, 67s used the "hat" to locate the spring.. maybe it is an early 67 rear but I have never heard of this...is the date code cast one of the webs at the bottom of the pumpkin? The earlier rears are definately narrower than the later,unfortunately my 66 cars are at another location so I cant measure at the moment.

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

Nope. The code is on the axle tube itself.

--Andy--

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1970 Chevelle SS Convertible
1937 Master Business Coupe
1996 S-10 Blazer
TC #551, ACES #3513
VCCA #35642
Yup, I'm Chevy Prejudiced!!!!

I know the code is on the tube, but the date is usually cast into one of the triangular webs at the bottom of the rear..x 00 x with a letter for month, number for day, and letter for last number of year...6 for 1966 or 7 for 1967...example A 23 6 would be jan 23 1966...most rears I find have this..

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70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
55 chevy prostreet

Just to add a little more to the confusion :
I just measured my 12 bolt - 3:31 posi from a 70 SS ... 54" inside of backing plate to inside of backing plate, measured at the extreem outside edge of the backing plates.
It is aprox. 1" wider, measured nearer the center of the backing plates.
I have read here a few times that 64-67's were 1 3/4" narrower than 68-72's




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Dean Call
Team Gold member #3
A.C.E.S. # 00235
N.C.O.A. # 4350
Mid America Chevelle Club (http://macc.chevelles.net) #001

chevelles.net (http://chevelles.net)

On 64-66 GTO rear ends the width is the same, 67 rear ends could go either way. The early 67 rear ends may be one inch less in width than the mid year 67 rear ends. The way to tell which rear end you have in a 67 is the spring mounting pad, if you have a flat mounting pad with a hole through the center and have clamp the spring to the pad you have the early narrow style rear end. I have a 67 El Camino with the latter style 12 bolt in it and have 1969 GTO rear springs in it. I measured the width once and I think it was about 61 inches drum to drum.

Droptop

Other codes on my carrier:

Back of "pumpkin" (drive shaft side) Passenger side triangle: GM4
Driver side triangle: 385914ON

That's all I can find. Thanks for al your help. Will be seeing you soon...

--Andy--

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1970 Chevelle SS Convertible
1937 Master Business Coupe
1996 S-10 Blazer
TC #551, ACES #3513
VCCA #35642
Yup, I'm Chevy Prejudiced!!!!

I was told the early 67-69 Camaro's have two differant lenght axles?
BTW 67 has the narrowest of all of the 'A' bodied cars. I have two 10 bolts out of 67 Chevelles and both measure 53 1/2" backing plate to backing plate. Me and Wally must have a couple of rare differentials http://www.chevelles.com/forum/tongue.gif

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Lowered '67 Elcamino
ZZ430HP / 4L60
"Canyon Carver"

Cardiac, My 65 and two 64 10 bolts measure 53 1/2 between backing plates and 2 5/8" out to the axle flange on each side. For a total of 58 3/4". I want a 12 bolt that is only 56" overall, so I guess I'll have to build my own.

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Philip Valentine
Gold Member #42
"Perseverance is not a long race; it is many short races one after another."
philip@chevelles.com

64elcamino

My 12 bolt housing came out of a 65 SS, it is the same as the one you are looking for.

I have the funny feeling that the 65 may have had a rear that was more narrow than other years. I tried calling Mark Williams, they say there is so much confusion on this that they make everyone measure the housing before ordering axles.

I have the 65 housing in a 67, fits fine.

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Wally
Gold #67
67 Malibu "Small Block"
90 SS454
71 Malibu "Small Block"
93 torch red vette