Team Chevelle banner
Status
Not open for further replies.

12-bolt rearend width questions

65K views 16 replies 12 participants last post by  Kirk's67SS 
#1 ·
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).]
 
#2 ·
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.
 
#3 ·
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.
 
#4 ·
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!)
 
#5 ·
<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).]
 
#6 ·
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"
 
#7 ·
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!
 
#8 ·
<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
 
#9 ·
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
 
#10 ·
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.
 
#17 ·
Status
Not open for further replies.
You have insufficient privileges to reply here.
Top