stiff lowering springs

[bigbrownbird]

I was wondering if anyone knew where I can find progressive lowering springs for a 78 that drops 1 INCH! or NONE! I can't have it too low.

Thanks,
Lee

[Gearworks]

if i remember correctly eibach used to make a set for our beloved birds...

[marine165]

Originally Posted by bigbrownbird

I was wondering if anyone knew where I can find progressive lowering springs for a 78 that drops 1 INCH! or NONE! I can't have it too low.

Thanks,
Lee

Lee,

I was recently lucky enough to get my paws on the MOOG spring catalog, and was able to pick out all of the springs that they sell that would fit my cougar (or your bird) So... how stiff do you want them? I think currently they're 325 lb/in in the front and 235 or something like that in the rear. The stiffest I've found for the rear are 266, so there isn't too much improvement there. But if you're crazy enough you can go all the way up to 1000 lb/in on the fronts! (Springs from some old dodge pickup trucks fit our cars)
I would reccomend something in the 750 lb/in category for the fronts, and then get LTD station wagon springs for the rear (262 lb/in), and then figure out how to put a pretty massive rear swaybar on! I've heard that you can put the front swaybar on the back if you modify the end links...
Hope some of this info helps! Let me know if you want me to look up any specific springs for you.

Mike

[Charles]

Thanx for the info Mike. I just tore down the front of my '79 for restoration and really want to stiffen up the suspension. The wagon springs for the back is a trick I forgot about but works well. I want to stay in the 500lb range for the front springs with no change to ride height. Can you help me with a part number?
Thanx, Charles

[marine165]

Originally Posted by Charles

Thanx for the info Mike. I just tore down the front of my '79 for restoration and really want to stiffen up the suspension. The wagon springs for the back is a trick I forgot about but works well. I want to stay in the 500lb range for the front springs with no change to ride height. Can you help me with a part number?
Thanx, Charles

Charles,

I think I have just the spring for you.

TRW/MOOG p/n = 5578
free length = 16.465 in.
rate = 569 lb/in.

This will actually raise the installed height by .69 in, but you can always trim it a little bit, since it has one tangential end on it.
It is better to get a longer spring and trim it down than get a spring that is too short. :)

Enjoy!

Mike

[Gearworks]

...and those are direct fit size wise? Since you have the "holy grail" Moog book, could you list both specs so our members can see the difference, and compare?

thanks
Paul

[marine165]

Originally Posted by Gearworks

...and those are direct fit size wise? Since you have the "holy grail" Moog book, could you list both specs so our members can see the difference, and compare?

thanks
Paul

Sure thing, Paul.

Actually, I'll do you one better. I'll attach the excel spreadsheet I made up with all the likely springs that are considerably stiffer without changing the installed height too much so you can look at your leisure. Remember that the stock spring specs are for a 351W with air conditioning...
Also, you will notice that there are two rows, one labeled 'change in installed height' and the other 'change in ride height'. The change in installed height is the change in height of the spring itself. The change in ride height is the change in the height of the spring multiplied by the ratio of the lengths of the lower A arm (the length from the ball joint to the center of the spring divided by the length from the center of the spring to the pivot on the frame, if that makes sense). I don't know that ratio, and haven't measured it on my car, so I just assumed it was 2, which is a common ratio. If anyone knows what this ratio actually is, or would like to take a tape measurer to their car to find it out, I'd be really interested to know!
If anyone is looking for a rate softer than the ones I have included in this spreadsheet, let me know and I'll look them up. But I have a friend with a 91 caprice and he put 840 lb/in springs in the front, and it rides very well, in my opinion. The harshness comes if you put stiff shocks on a car rather than the springs.
Which actually is another consideration with stiff springs; you will have to do some research to see if you can find a shock absorber stiff enough to give you the proper damping ratio for these considerably stiffer-than-stock springs. The stock shocks just won't be up to the task! If anyone has found good, stiff front shocks that they could reccomend, I'd really like to hear it!
When I put the LTD wagon springs in the back, I got some KYB Gas-a-justs, and they do just fine. I'd reccomend them.

Okay, here's the file!

Enjoy.

Mike

P.S. I had to attach it as a .zip file, because for some reason .xls isn't a valid file extension to attach on this forum... :rolle go figure.

[429Thunderbird]

Great Info,

I bought a set of springs last year (8528) but I have yet to install them. I was told they have a high rate, and are for a LTD(?), and they should fit the Bird. I want something stiff, since the extra weight of my 429 makes my front end dip a lot ( still have the original 400M springs). Let me know if you have any info on these springs. I don't mind cuting them a little to lower the height if I have to. Ultimately what I want is to lower the car about 1.5" - 2" and stiffen the front end (700 - 850 rate). If you can reccomend something else, I will return these and buy another pair.

Look forward to your response!!

JOE

[Charles]

Originally Posted by marine165

Charles,

I think I have just the spring for you.

TRW/MOOG p/n = 5578
free length = 16.465 in.
rate = 569 lb/in.

This will actually raise the installed height by .69 in, but you can always trim it a little bit, since it has one tangential end on it.
It is better to get a longer spring and trim it down than get a spring that is too short. :)

Enjoy!

Mike

Thanx for reply and all the great info. Back in the '80's I had a '77 Ranchero that I wanted firmed up. An old stock car racer gave me spring specs to take to the local suspension store :nopity who sold me springs and gave me specs on what sway bars to use front and rear. After I put the 4 springs and 2 bars on the Ranchero, the handling was unbelievable. Handled alot like my buddy's '79 Trans Am. Sure wish I had the specs for these parts now. Charles

[Charles]

Thanx Marine165 for the great work put into this issue.
But since I'm looking for stock height and higher spring rate, I went to Coil Spring Specialties. These guys do all the math for you. Not cheap at 130.00 /pair, but you get what you want. By the way, Bigbrownbird, They can supply stiff springs to lower your bird. Any height, any rate, whatever you need. E-mail Dave at [email protected] if interested

[Debber78Bird]

Hi, my wife recently bought a 78 T-Bird, all original and has been sitting since 1987. I plan to go thru the whole suspension and found your thread thru a Google search. Do you still have the file you mentioned in this post? I want to put stiffer springs on the car and lower the front end slightly. Thanks, David