My dad just bought a 1969 Firebird 350 2bbl hardtop that we have a problem with it sitting unevenly, mostly noticeable in the rear. When we got it the drivers rear tire would scrub over most bumps. After looking and seeing how worn out looking the springs were, and that the previous owner had put some sort of helper springs on it, we decided to purchase a set of John R Springs. After getting them and only replacing the drivers side it was apparent that there was still a problem, and after a few days settling, it was bad enough that we decided to put a set of lengthened shackles on it, but it seemed the height was the exact same. Before we even put the passengers side on, we decided to send them back that they must be weak as they appeared to be almost flat despite coming with a pretty good arch. We removed them, sent them back figuring that they were just cheap springs. We replaced the factory for the time being and now even with the lift spring it was actually sitting on the tire. So we called year one, they told us that they sold Detroit Eaton springs, and figuring it was year one, they should be good. Today we put the drivers on again, and started it off on the lift shackle which is about 4 inches of lift, and its still sitting at basically the same exact height. One thing to ad is that the wheels currently on it are wider and sit out enough that when its low it is actually hitting the fender lip. We are just at a loss for how such a simple system can be causing so much trouble while the passengers side always sits higher than a brand new spring, and the car still appears to sit towards the rear. Please HELP! We're tired of not being able to drive such an amazing car. Thanks for any information.

So every spring you buy is sitting too low? Sounds like you need heavier springs.

There are many options for springs out there for these cars. Here's Eaton's website, and as you can see there are multiple offerings in part numbers for these cars, depending on desired ride height, heavy vs std duty, engine sizes, coupe/convertible, etc:

http://www.eatonsprings.com/67-69firebird.html

Rather than going thru a 3rd party to buy springs, I'd recommend chatting with their tech support directly so they can assist you in your decision.

The fact that you have non-standard/oversize tires will complicate things greatly, and my require quarter panel/wheelhouse modification to fit if you really want to run whatever wheels/tires you have.

If you provide specifics of exactly what you have, maybe someone here with a similar setup can help. But I believe you will need to provide tire size, wheel size, exact spring part numbers you have attempted, etc.

Yes I've had a total of 3 different springs on the one side, but have kept the same for the other side so far, now if I put the ones on the other side, it may have the same issue. The tires are definitely wider, but for now we're trying to just make it driveable rather than basically sitting on the tire. We have some Rallys for it, but no money for tires cause we just spent almost 400 on the new springs. To order the springs, rather than website we called the tech line at year one, and they asked all the specifics on the car and we ordered over the phone, but even though as dependable as I would believe them to be, theres always the possibility it was messed up, but to have the same height as the others I figure unlikely. I can tell that the wheels do seem to push the tires out more, but all the pictures I see the tire to fender edge still has more gap than mine, where mine is almost tucking tire on what should be a stock height. I may end up just having to send the springs back at the cost of 40 dollars shipping, but I would rather figure out what the actual problem is. Is there any possibility the car is bent or anything? It seems like if that were the case none of the doors nor trunk would line up. Also as far as choices of springs, we started with the 5 leaf standard duty made by John R Springs, and now have the 4 leaf which were supposed to be heavy duty Eatons. It seems like no matter which one of the holes we use on the lift shackles it still sits at the same height somehow, which makes no sense

the rear will sit uneven if your front subframe is crooked...probably bent ,it twists the car ...this is one of those deals where you are looking at the result rather than cause when looking at the rear....check out the subframe...it may be the culprit

Ok, I've got a buddy thats been in body work for many years, I'll take it to him and let him put it on a lift and check it out. If it is a bent subframe, how much/hard is it to replace? Just doesn't sound like a good thing. Also you think that it would cause that much in the rear end, but no misalignment of anything else?

They can pull it if its not bad. Ive had mild bends pulled for 200.00 at my local shop. (kids running off roads and hitting stumps..lol)

I hit enter too quick . my bird was 90% rust i removed way too many parts at once. i was afraid of having a crabbing crooked car. i used 4 laser levels (20 bucks each) pointed plumbobs and the frame spec sheet to check everything BEFORE i welded anything. i had the shop down the road from me throw the car on the frame jig i was within 1/16" or less in every direction. i spent probably a week just setting up and tripple checking everything. I started with the center line of the car, and worked my way from there.

Worn body mounts could also cause the front subframe to sit incorrectly on the body which may raise the rear.

Another problem is if subframe connectors were welded on with worn body mounts. Then when new ones are installed the rear becomes shifted.

Where in SC?

Check and make sure the front passenger side coil spring is seated. I had the same problem and felt inside and could feel that my spring had to spin about two inches more to fully seat. I was going to address this but I changed my engine from a Chevy 350 to a Pontiac 400. The Pontiac engine is sitting more on the passenger side, it seems to have solved my problem.

If you google it you will see that it is common and the front passenger coil spring is the main culprit.

you can always use air shocks to set the height where you want it (left and right independent). thats what i've been doing for a few years now.