I just finished swapping my 10 bolt for a new 12 bolt and the rear is sitting too low. I used stock springs from ground up, lift bars, tubular upper control arms and KYB shocks from UMI performance. I figured the stock springs would be fine because the ride height with my old worn out springs were good so I figured new stock springs would be perfect. I like to have the rear slightly higher than the front or at least even. Its actually sitting lower now! The lift bars are a few inches from hitting the ground and im worried that they might scrape the ground if I try and go over any bumps. I will post pics later on. I am running 295 50 R15 tires. Am I going to need to get new springs?

I just finished swapping my 10 bolt for a new 12 bolt and the rear is sitting too low. I used stock springs from ground up, lift bars, tubular upper control arms and KYB shocks from UMI performance. I figured the stock springs would be fine because the ride height with my old worn out springs were good so I figured new stock springs would be perfect. I like to have the rear slightly higher than the front or at least even. Its actually sitting lower now! The lift bars are a few inches from hitting the ground and im worried that they might scrape the ground if I try and go over any bumps. I will post pics later on. I am running 295 50 R15 tires. Am I going to need to get new springs?

Springs won't get the lower arms any higher off the ground. You would have to go to a tire with a taller sidewall if they are anything like the old SSM lift bars they were pretty low to the ground too!:)

I plan on getting taller tires real soon. Any suggestons on getting the rear to sit higher.

Either spacers or different springs. I use the following site to find stock springs that will get the height needed.

http://www.classiccarsprings.com/chevy/8chevelle.html

You can measure the compressed or installed height of the springs now and determine the weight on them using the spring rate and the uncompressed height. Using the weight you determine, you can hopefully pick a new spring that will have the installed height you need. Make sure the spring ends are what you need.

Let me know if you need any help.

why raise the rear when you can just drop the front :D...i kid i kid

Ok this is the springs that I got, the part number is 6319. The springs are incredibly to small and im looking to get a much larger spring. I like to have the rear site slightly higher than the front. I could use some suggestions on what springs to buy. Im thinking of about a 15 inch install height what do you guys think. Will that through my pinion angle off too much? Thanks. This is the site I got my info from. http://bbb-carb.com/moog_Coil_Springs.htm

install height9.00

load rate 616.0

spring rate119.2

free height 14.17

i think that moog or trw makes a hd spring that you can get from the parts stores.

Big question, did you swap in a Chevy rear-end or a BOP rear-end? I swapped my 10 bolt out for a posi donor from a Cutlass. The rear-end are slightly different in either the spring perch or upper control arm mounting location causing the rear-end to sit rotated towards the rear slightly. This casues the spring perches to sit lower to the ground, causing the car to sit a bit lower. A lot of cause and effect here.

I drove mine quite a bit without any issues. I didn't go crazy with it becasue I'm sure I have a very small issue with the pinion angle. I don't think it will be an issue because I don't race and I don't have over 400 HP going to that rear-end.

I think a cure to my problem would be to A)find a Chevy 12 bolt $$$$ or B)replace the stock upper control arms with adjustable arms to rotate that differential forward enough to correct it. I'll make that decision when the time comes, the car is down for a while.

Its a 12 bolt from a 70 chevelle, I ran the numbers. Overpaid 600 bucks for it, and its been totally rebuilt. Also what load rate/spring rate.

Using your 6319 springs with a 119.2 lb per inch spring rate for base numbers, the following springs will raise the rear about the amount indicated:

CC507 +2.4 inch (175 lb per inch spring rate)
6381 +2.2 inch (198 lb per inch spring rate)

Of course, the ride will be rougher due to the higher spring rates.
These springs are off the shelf for about $68. Both are pigtail by pigtail.

I dont think 2 and a half inches will be enough. Im at base right now and dont have the pictures on me. Its seriously sagging way too low. Is there any other factors that would make my rear end sag besides the springs?

Its all about spring length, spring rate and weight on the springs. The only things that could change it drastically are the contact postions of the top and bottom of the spring or the weight on the rear of the car. You say it is a stock 70 rear, so the bottom perch should be correct. What about the where the spring contacts on top? Do you have anything special in the back of the car that would increase the weight?

Its all about spring length, spring rate and weight on the springs. The only things that could change it drastically are the contact postions of the top and bottom of the spring or the weight on the rear of the car. You say it is a stock 70 rear, so the bottom perch should be correct. What about the where the spring contacts on top? Do you have anything special in the back of the car that would increase the weight?

Yeah,,,like maybe a 1/2 dozen dead bodies : ) ???

Its a 12 bolt from a 70 chevelle, I ran the numbers. Overpaid 600 bucks for it, and its been totally rebuilt. Also what load rate/spring rate.

Totally rebuild 12 bolt posi for $600 doesnt sound like over paying to me. :noway:

Are ya sure you don't want to lower the front? It'd look killer all low and mean...

The rear was 600 alone without the rebuild. The rebuild was 1200 with new gears, posi, and axels. Then about 500 bucks worth of stuff from UMI and ground up. I dont want to go any lower on the front springs, im not really going for that look right now. Plus my headers will be scraping on the ground. I already have a problem with scraping the headers sometimes. Here are some pics. Tell what you guys think.

http://img134.imageshack.us/img134/3386/img1283r.th.jpg (http://img134.imageshack.us/my.php?image=img1283r.jpg)
http://img134.imageshack.us/img134/4826/img1285o.th.jpg (http://img134.imageshack.us/my.php?image=img1285o.jpg)
http://img134.imageshack.us/img134/7977/img1286.th.jpg (http://img134.imageshack.us/my.php?image=img1286.jpg)
http://img134.imageshack.us/img134/518/img1287.th.jpg (http://img134.imageshack.us/my.php?image=img1287.jpg)

Now that the pics are posted, do you guys think that a taller wheel and tire combo will fix the problem or are the tires going to start rubbing because the springs are too low.

For $100, you could just put some drag bags inside the rear springs to lift them up as high/low as you wanted.


http://store.summitracing.com/partdetail.asp?autofilter=1&part=BMR-DB001&N=700+115&autoview=sku

http://static.summitracing.com/global/images/prod/large/bmr-db001_w.jpg

Those wont work because it says "without affecting ride height" which is what I need.

Those wont work because it says "without affecting ride height" which is what I need.

It's what I use, have for years. "Without affecting ride height" unless you want them to is what it should say. They work great.

How do the drag bags work? How much more lift can I get out of them, and what does it do for performance at the track? Im glad you wrote back im really interested in getting a set of these.

The idea behind the bags is that they level-load your traction at the track. Typically the left rear will grab first, start to spin, then the traction moves to the right rear next as the left side of the car rises. The bag, with only 15? lbs of pressure will put more force on the left side, just enough to equalize the two sides when launching, allowing for an even launch.

That's my understanding of it -

For height, put more air in both sides, to get what you want. There is a limit of course, but 1-2" is a piece of cake. Drawback, your springs are less springy, so the ride is a bit tighter.

FWIW, just another idea, these can be made (to suit your needs) at a machine shop.

The underside is hollow (female) to accept the male on the rear.

They simply get installed between the rear-end spring perch and the spring.

If the axle tubes interfere you can machine a flat in the base of the spacer for clearance.

If you raise your car over stock you should always use some type of shock extender as well.

http://i277.photobucket.com/albums/kk75/ls7chevelle/war307211.jpg

Im ordering some drag bags today, thanks.

I used a pair of coil spring spacers off a buddy's Jeep TJ. He went with another lift and they worked perfectly. gave me the 2 inches needed when I replaced the front springs and holy cow, gained 2-3 inches up front. Was not expecting that to happen. In time it will settle in and be even. Just the way I want it.