12-bolt rearend width questions - Chevelle Tech
2001 General Tech questions from 2001

 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 17 (permalink) Old Sep 14th, 01, 6:07 AM Thread Starter
Tech Team
 
Join Date: Apr 2001
Location: Yukon, Oklahoma
Posts: 154
Got a quick question for you guys about the width of a 12-bolt rearend. I just bought a 12-bolt posi rearend from a guy. He said that the rearend came out of a '70 chevelle. The rearend was just built, so it is in perfect condition. I took the rearend out of my Chevelle last night, and I noticed a few things.(I have a '71 Chevelle) The new rearend is exactly 1" shorter than mine, and the emergency brake cables are about 2" shorter. Judging by the axle codes, the new rearend is actually from a '66 Chevelle (I think) Will this bolt up to my Chevelle with no problems? Will I have to switch the emergency brake cables?

Just what does the DUDE have here?

------------------
Mark "THE DUDE" Skoch
1971 Malibu
"If you ever reach total enlightenment while drinking beer, I bet it makes beer shoot out your nose."
THE DUDEMOBILE
(DUDE POWERED!)

[This message has been edited by THE DUDE (edited 09-14-2001).]
THE DUDE is offline  
Sponsored Links
Advertisement
 
post #2 of 17 (permalink) Old Sep 14th, 01, 6:28 AM
Tech Team
 
Join Date: Aug 2000
Location: Chicago, IL
Posts: 54
66 & 67 12-bolts are inch narrower than 68-72 (which are all the same). This rear end should bolt in directly, and actually give you a bit more room to run wider tires. Unfortunately, I don't know about the interchange of lines and cables.
esq1995 is offline  
post #3 of 17 (permalink) Old Sep 14th, 01, 9:14 AM
Lifetime Premium Member
Dave
 
Join Date: Mar 1999
Location: Agawam, MA
Posts: 1,899
Actually it's 65-67 that are narrower and only the 67 will work as a direct bolt in due to the differences in spring design. 65 & 66 have flat spring perches which are not compatible with the later springs. Second, rear axle width has absolutely no bearing on the size tire you can fit inside the wheel well. Rim width, backspacing and wheel well size are the determining factors. So, if the spring perches are the same as your '71 the axle will work with no modification but the emergency brake cables are "application specific" and will have to be changed if they are in fact 2" shorter.
David Bates is offline  
post #4 of 17 (permalink) Old Sep 14th, 01, 9:33 AM Thread Starter
Tech Team
 
Join Date: Apr 2001
Location: Yukon, Oklahoma
Posts: 154
Thanks for the replies guys!

The rear-end code is CF which I guess could also be a 67 rear-end if I am looking at the book right. The spring perches on the new rearend look just like the ones that are on my '71 rear-end. I guess all I will need to do is change out the emergency brake cables and it should bolt right in.

Right????

P.S. Will it set my wheels in 1/2" on either side as long as I am using the same wheels as before?

------------------
Mark "THE DUDE" Skoch
1971 Malibu
"If you ever reach total enlightenment while drinking beer, I bet it makes beer shoot out your nose."
THE DUDEMOBILE
(DUDE POWERED!)
THE DUDE is offline  
post #5 of 17 (permalink) Old Sep 14th, 01, 10:25 AM
Gold Founding Member
Dale
 
Join Date: Aug 1998
Location: Lawton, Oklahoma
Posts: 19,495
<BLOCKQUOTE>quote:</font><HR>Originally posted by David_Bates:
Second, rear axle width has absolutely no bearing on the size tire you can fit inside the wheel well.<HR></BLOCKQUOTE>

Beg to differ. While other factors do come into play, a narrower rear end will give you more room from drum to fender lip requiring less backspace required on the rim itself. Could be that's why folks who run ProStreet have tubbed wheel wells and narrowed rear ends...the ability to run wide tires/wheels with a lot of negative offset.

9-15-01

Let me edit my response and do a bit of retraction. The size tire that will fit inside the stock wheel well should be constant. The axle width would determine the correct backspacing required - hence I agree. It was late when I chimed in and didn't fully read the response as carefully as I should have.

------------------
Dale McIntosh
TC Gold #92
ACES #1709
http://www.dalesplace.com

[This message has been edited by Dale McIntosh (edited 09-15-2001).]
DaleM is offline  
post #6 of 17 (permalink) Old Sep 14th, 01, 1:32 PM
Tech Team
 
Join Date: Aug 2000
Location: Chicago, IL
Posts: 54
I hate to get all puckered up on this, but David, it's not always what you say as much as how you say it.

I appreciate accurate information as much as anyone, and am fully open to constructive criticism, but try leaving the ATTITUDE out.

Just a suggestion.



------------------
1971 Chevelle w/ 402 Big Block and TH350
SS "RepliCar"
esq1995 is offline  
post #7 of 17 (permalink) Old Sep 14th, 01, 4:19 PM
Lifetime Premium Member
Hoarder Deluxe
 
Join Date: Jul 1999
Location: Poughkeepsie NY
Posts: 3,430
Also, the 65/6 rears with the flat spring mount will work fine with the later springs, you just use the stock 66 mounting hardware instead of the "hat" to locate the spring.

------------------
Dave
70 chevelle ss396 conv
66 chevelle ss396 hdp/conv
72 chevelle
TC member #493
Never forget Earnhardt!
drptop70ss is offline  
post #8 of 17 (permalink) Old Sep 15th, 01, 5:17 AM
Gold Founding Member
Dale
 
Join Date: Aug 1998
Location: Lawton, Oklahoma
Posts: 19,495
<BLOCKQUOTE>quote:</font><HR>Originally posted by THE DUDE:
Thanks for the replies guys!

The rear-end code is CF which I guess could also be a 67 rear-end if I am looking at the book right. The spring perches on the new rearend look just like the ones that are on my '71 rear-end. I guess all I will need to do is change out the emergency brake cables and it should bolt right in.

Right????

P.S. Will it set my wheels in 1/2" on either side as long as I am using the same wheels as before?

<HR></BLOCKQUOTE>

I would certainly think so. I had just the opposite (a 69 rear end in my 67) for about 10 years. When I finally found a 67 rear, the swap was direct. No cables to change or lines to modify. Using the same wheels/tires on both did bring the tires back in from the outer lip with the narrower rear end.

------------------
Dale McIntosh
TC Gold #92
ACES #1709
http://www.dalesplace.com
DaleM is offline  
post #9 of 17 (permalink) Old Sep 15th, 01, 6:00 AM
Tech Team
Doug
 
Join Date: Aug 1999
Location: Mid-Missouri
Posts: 866
Hey DUDE!
Can you hear me over all this commotion?
To answer your question, yes, it will pull you existing rim/tire combo inward 1/2 inch. I have almost the same setup on my project. It will allow me to run a wide rim with less back space (and the rim will look deeper on the street side).

------------------
Doug, Chevl71
Team Chevelle member #625
Gateway Area Chevelle Club member CM028
(OO ss OO)
chevl71 homepage
chevl71 is offline  
post #10 of 17 (permalink) Old Sep 15th, 01, 7:30 AM
Lifetime Premium Member
Dave
 
Join Date: Mar 1999
Location: Agawam, MA
Posts: 1,899
esq1995,

I was only stating fact with no "attitude" intended. I've seen too much of that recently and was trying to be as neutral as possible. Iguess I'll have to try a little harder.
David Bates is offline  
post #11 of 17 (permalink) Old Mar 28th, 07, 5:49 PM
Senior Tech Team
Larry Joe
 
Join Date: Jan 2007
Location: tulsa okla
Posts: 1,038
Re: 12-bolt rearend width questions

I have a 66 chevelle with a 12 bolt that I was under the impression was the correct short rear as it was the right length Yet it says its a 68 early production. I never questioned it. What is the correct measurements from a 66 12 bolt inside backing plate one to another?

blubu

Last edited by blubu; Mar 29th, 07 at 1:15 AM. Reason: rear end length
blubu is offline  
post #12 of 17 (permalink) Old Mar 18th, 11, 4:33 PM
rick
 
Join Date: Feb 2011
Location: Los Angeles
Posts: 2
Re: 12-bolt rearend width questions

it 52" if that answers any questions
slickrick is offline  
post #13 of 17 (permalink) Old Mar 18th, 11, 4:35 PM
rick
 
Join Date: Feb 2011
Location: Los Angeles
Posts: 2
Re: 12-bolt rearend width questions

anything from 68 on is 54 and a quarter
slickrick is offline  
post #14 of 17 (permalink) Old Mar 18th, 11, 6:57 PM
Lifetime Premium Member
Papa
 
Join Date: Oct 2005
Location: 1/4 mile from Arnold, ND
Posts: 1,996
Re: 12-bolt rearend width questions

I measure 1964-67 = 54 1/4" & 1968-72 = 55 1/4" backing plate surface to surface.....................
Mr Chevelle is offline  
post #15 of 17 (permalink) Old Mar 18th, 11, 8:30 PM
Lifetime Premium Member
Rick
 
Join Date: Mar 2001
Location: Sigel,Illinois
Posts: 1,045
Garage
Re: 12-bolt rearend width questions

I hope that The Dude ( the original poster) has found his answer since it was first asked on September 14 2001.
1968 is online now  
Sponsored Links
Advertisement
 
 

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome