I just replaced my rear springs in my 66 and discovered that it does not have a retainer plate and bolt at the bottom (axle seat) as indicated in the manuals.

Am I supposed to have one?, or could it be because of the '70 rear end?

Can't get the springs off without removing the retainer, unless you don't have a rear from 66 or 65. Are your spring perches flat?

my 66 and 67 has the retainer plate

My spring perches are not flat. Could this be why? Did the '70 chevelle rear ends not use them?

sounds like it is not a 66 rear, you think it might be from a 70? that would sound like what you have.

I know for a fact that it is a '70 rear end.
I'm gathering that these did not have any kind of retaining plate/bolt?

No retainer on 67 and later

I am not sure if I have a 66 rear end or not. I think I do but not sure? Does anyone have any pics of one so I can tell? My rear end does not have a retaining bolt. If I have a 66 it is a must?

Thanks for any help didn't mean to steal your post just curious,

Thanks all.

GSOUPME,
I believe the best way to tell your year of manufacture is to check the numbers on the axle.

Thanks again to this thread, apparently the early rear axles had a flat spring perch thus requiring something to keep it from shifting around. The 70 rear axle I have is raised at the center of the perch to prevent the spring from shifting or sliding off..this apparently was the only concern for GM.

Everyone says that the 68 to 72 12-bolts are a direct swap for a 64-67 with the only difference being that the later rears are 1" wider; and lower control arm mounts are in the same place. Have heard that the ears for the upper control are not exactly in the same place. The 65-67 ears are approximately 3/8'th of an inch more forward. If so wouldn't this change the pinion angle, unless your using adjustable upper control arms? And the rear u-joint not in tune with the front u-joint unless you shimmed the transmission. The 67 rear is the same as the 65 or 66 except the spring perch is domed instead of being flat and thus there is no need for the bolt and retainer to hold the spring in place.

If you have flat spring perches then you have a 65 or 66 rear. If you have a domed perch it might be a 67 or a 68-72.

I read that last night about the pinion angle being different as I was searching the net.

Everyone says that the 68 to 72 12-bolts are a direct swap for a 64-67 with the only difference being that the later rears are 1" wider; and lower control arm mounts are in the same place. Have heard that the ears for the upper control are not exactly in the same place. The 65-67 ears are approximately 3/8'th of an inch more forward. If so wouldn't this change the pinion angle, unless your using adjustable upper control arms?. And the rear u-joint not in tune with the front u-joint unless you shimmed the transmission.


May be true, I haven't heard that...

BUT, I have never heard of anyone having problems after swapping in a later rear in an early Chevelle... At least any problems pertaining to pinion angles...

Guys...for what it's worth...I have a 68-72 12 bolt under my '66 Camino..other
than it being a touch wider(and no retainer plates!)it went right in and I've had no problems with it.

Middle of the 67 year model and some 67's had flat spring perches with spring retainer. I have a 67 12 bolt with this design. They change to a round raised ring that the spring slides over and cannot move around.

look at this thread:
http://www.chevelles.com/forums/showpost.php?p=870045&postcount=6

Everyone says that the 68 to 72 12-bolts are a direct swap for a 64-67 with the only difference being that the later rears are 1" wider; and lower control arm mounts are in the same place. Have heard that the ears for the upper control are not exactly in the same place. The 65-67 ears are approximately 3/8'th of an inch more forward. If so wouldn't this change the pinion angle, unless your using adjustable upper control arms? And the rear u-joint not in tune with the front u-joint unless you shimmed the transmission. The 67 rear is the same as the 65 or 66 except the spring perch is domed instead of being flat and thus there is no need for the bolt and retainer to hold the spring in place.

If you have flat spring perches then you have a 65 or 66 rear. If you have a domed perch it might be a 67 or a 68-72.

I would agree with all said above. I did alot of research when I was swapping a 12 bolt into my 65. I also found all of the same info from several different sources here and elsewhere. The only thing I could add is that a 67 can have both the flat and domed style spring perches, I believe they switched from the flat style to the domed style mid year.

Have a shortened 70 rear on my 64 with stock adjustable uppers no problem with pinion angle.

Marcus

I'm sorry to ask but--the springs will interchange? I have read somewhere on this forum that you have to buy the later springs to use the later rear.
Thank you and sorry if it's a dumbass question.--Josh

I'm sorry to ask but--the springs will interchange?Sort-of... see below.

I have read somewhere on this forum that you have to buy the later springs to use the later rear.This is incorrect, you use the springs for whatever year the car is, regardless of what year the axle came from.

All 64-72 rear springs had a pigtail at the bottom of the spring which is the same size, so it will fit inside the 64-66 bolt-on retainer plate, or over the raised part of the 67-72 perch. Which type of perch doesn't really matter, they'll all work.

The difference is the TOP of the springs, and the shape of the spring-pocket they go into on the frame of the car.

'64-66 used a full-width coil on the top of the springs, and pigtailed bottom.
'67-72 used a pigtail at both top and bottom.

I know '64-66 springs will work fine on a '67-72 frame, but I'm unsure whether the 67-72 springs will work in a '64-66... I doubt it though.