The '64 to '67 rear end is 60 inches wide over all. The '68 to '72 rear end is 61 inches wide over all. That is not myth or best guess, that is fact from many years of experience.

 

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The stock factory Rear Ends in 68 - 72 Chevelles are wider than the 64 - 67s.
A. First you should clarify which Rear End width you have in your car .
Here is the source for rear end widths http://chevellestuff.com/qd/generic_rear_axle_info.htm
* 1964-67 Chevelle rear ends were manufactured by the Chevrolet Gear and Axle Division.
The housing measures 53.25 inches from backing plate to backing plate
and with the brake drums in place, the total width is 60.00 inches.
Axle tube flange-to-flange is 54.25 inches.
* 1968-72 Chevelle rear end housings measure 58.5 inches from flange to flange,
and with the brake drums in place, the total width is 62.5 inches.
(Note: Other sources put the total width at 61.125" to 61.25".)
Axle tube flange-to-flange is 55.25 inches.
* A second measurement to check is centerline distance between spring perch seats.
1964-1967 are 35 1/16 inches between seats
where 1968-1972 are 34 31/32 inches.

 

Go to Moser or Jegs for replacement axle length of car in question then multiply by 2 and add 1" for the cross pin, pretty simple...........

 

I have to disagree with the '68 to '72 measurements in that article. I know for a fact that the '68 to '72 rear ends are exactly 1 inch wider than the earlier rear ends. The axles in a '64 to '67 rear end are 29 9/16 inches long and the axles in a '68 to '72 rear end are 30 1/16 inches long. Add 7/8 inch for the cross shaft in the differential and they come out to 60 and 61 inches wide. I've built more of these rear ends than I can count and replaced an unknown number of these axles and I can say without any doubt that these measurements are correct. Some manufacturers list their axles as 29 5/8 and 30 1/8, but that doesn't really make any difference.

 

Freddie I got that info from Team Chevelle Site's Tech Info by Year

If it is wrong then maybe the admin at Team Chevelle should delete it from their site or put a disclaimer/ or this post # etc.

 

Some of the late 67' 12 bolts were an inch wider as well.

 

that article that was referenced was what i was confused about...seems those measurements are repeated all over the internet. Thanks "BIG GEAR HEAD"! I was hoping you would chime in...I have a 2.73 geared 10 bolt with no funds for a 12 bolt quite yet. Seems to be alot of cheap 10 bolts around here with some having 3.30 ish gearing...thought i might go that route and they are in the earlier years so just wanted to make sure. i thought one inch shorter on each side might look a little dorky but i could live with 1/2 inch. Thanks!

 

There is a lot of bad information on the internet, especially about rear ends. There is a rear end measurement chart that is very popular, but it has a huge amount of mistakes on it. The problem is that you can't get the correct information out there enough to cover the bad information.

 

lets see if i have this right...if i buy a 66 rearend for my 72 then i will need 66 springs to fit on the perches ? i can't use my 72 springs ?

 

You can use your '72 springs. You will need the washer things and bolts that hold the bottom of the spring to the flat spring perch.

 

What Freddie says and 66 springs wont fit the frame on a 72.

 

thanks everyone !

 

Yea, I knew that you had got that from the other sight. I hope it didn't sound like I though you came up with it yourself.

That's not the only place that I've seen that measurement. I think someone years ago posted that measurement and several other sights have adopted it as the truth. I don't know how to go about correcting it all over the web, but it's just another example of why you need to be careful about what you believe on the internet.

Is there actually a difference in the distance between the spring perches on the early and later rear ends? I've never measured that and I assumed that they were all the same.

 

Is there actually a difference in the distance between the spring perches on the early and later rear ends? I've never measured that and I assumed that they were all the same.

I belive the 68-72 perches sits little higher vs 64-66? At least that was my experience when I changed my 64 rear to a 70 rear never measured the distance between them and my 64 rear is long gone but guess that 3/32" difference isnt noticeable if there even is a difference?

 

As far as the early rearend in the later car, I used the later springs, and made some aluminum discs that I bolted to the flat spring perch to mimic the later style locating "hub" for the bottom of the spring. Been in my car like that for probably at least 15 years with no problems.
Jim

 

I have a 70 Chevelle with the original 12 bolt. A while back I made a drawing of the rear of the car in order to find wheel/tire clearance. My rear axle measured 60-7/8 from axle flange to axle flange. I'd like to attach the drawing, but the file size is too large.