I want to replace the original rear leaf springs on my 69 350 auto convertible. I bought the car in '71 and decades ago added shackle extenders to level the car. It came with 4-leaf springs.

The Performance Years catalog lists a 5-leaf, adding that it would give a 1 1/2 to 2" additional lift on a '69 Bird.

Classic Industries gives more detail but seems confusing. They say 4-leaf springs were used on heavy duty and 400 models and has a spring rate of 126#. They also say the 5-leaf was originally installed on standard applications and lower performance models yet it has a spring rate of 143#.

I don't want shackle extenders again so I want to make sure new springs will make the car level or maybe slightly higher in the rear. What I read in these catalogs isn't clear to m e. I'd think the 143# springs would've been used for heavier duty application?

Phil

The ride height will depend more on the arch of the spring then the rate and the number of leafs is not really a factore to the spring rate or the ride height.

That is why chooseing springs is so darn difficult.

And I thought it was just ME!

Should I be asking people at Classic?

Any other experiences or suggestions?

Phil

I talked to the sales staff at Eaton Spring Company. They were very helpful, and seemed to have a lot of options.

http://www.eatonsprings.com/

Thanks for the link. I had seen them mentioned when I did some searches here before posting my question. I can remember one post mentioning that their pricing was good so "why buy from the middleman". Glad to see you found them helpful.

Phil

There is also a 3 leaf spring that is never talked about.Thats what is in my T/A,I've also seen them on a Ho 350 car before.

Andy,

That's why I'm confused about these things. A friend had a 67 Camaro with the mono-leaf and had a horrible time with it wrapping up on acceleration.

So I'd think 3-leaf would be better, 4 better yet, and 5 the strongest. Obviously, standard logic doesn't apply.

I've emailed Eaton and should learn more next week.

How come when I'm typing my reply the screen keeps jumping around and I can't actually see what I'm typing? I go to a dozen forums regularly and never seen this problem before.

Phil

Phil,let me know what you find out from Eaton,when I asked them about 3 leaf springs they had no idea what I was talking about but said they could copy mine if I sent one as a sample.In 1967 all F bodys had mono leafs,when they went to multi leafs the total stack height of the springs is the same regaurdless of leaf count.Spring rate changed by leaf count, the fewer the springs the higher the rate because the springs were thicker when there were fewer of them.

Thanks Andy... THAT makes sense!

Mike (Spring Guru) sent me to this page:
http://www.eatonsprings.com/67-69firebird.html

I hope to check it out later today.

Phil