Rear leaf spring recommendation for 67 Barracuda

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512Stroker

512Stroker

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Looking to replace my wore out rear springs.
8 3/4 Sure grip 3:23 gear, 340
I am running 28 inch tall 15 in rear tires and I am concerned with wheel well clearance.
Anyone with a real world experience recommendation would be greatly appreciated.
I only want to do this once so no keyboard mechanics please.
Thanks

IMG_20180804_103724077_BURST001.jpg
 
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If it were me, I would contact someone at either ESPO Springs and Things, or Eaton Spring. I am by no means an expert on leaf springs, and don't want to be a "Keyboard mechanic". I just know that they offer different springs with various spring rates, and I also know that you can order +1", and +2" springs to give you more height in the back to help clear your tires.

If you want guidance on what springs, why not go to the experts. I have heard a lot of good things about both of those companies.
 
If you want to do it once.
Weigh the car at race weight. Get the weight on the rear wheels alone.
Remove the current springs.
Measure the free arch,
Measure the how far each compress when a heavy weight is placed on them.
>The way I do this is by standing on them after weighing myself, or whoever is the victim.
> be care full when getting off the spring, it can throw you!
Now you can calculate the spring rate of each one, and you've measured the free arch.
Depending on how beat up the spring is, the rate and free arch may be less than new. Especially the right side.
But it tells you exactly where the springs are at. So you can then select new ones and know what they will do.

One spec that can't be easily measured or figured is the spring ratio.
Look at the number of leaves, where the second leaf end is positioned under the eye, and the thickness of the main leaf and the 2nd leaf.
This gives a pretty good idea of what you have, and what to ask about when shopping.
 
Forgot to mention what to do with the weight on the rear wheels.
Use this with the spring rate to figure out the arch when loaded.

This way its possible to figure how the car will sit when using springs with different rates and free arches.
 
ESPO.com (springs and things)
A 1 inch over bend is what I have used in the passed and that cleared the tire height. Your biggest concern is width. In jounce (compression of the springs and shocks) the tires should t stick out of the wheel wells.
 
My concern is that the car sits high as it is. You are using ride height to get clearance for tires/wheels that most likely do not fit the car properly.
 
roccodart440 said:
My concern is that the car sits high as it is. You are using ride height to get clearance for tires/wheels that most likely do not fit the car properly.
Click to expand...
Good call, that's what's happening - taller tires - taller ride height.
I would normally tub the car to fit the tire size, but this is an original CA car, rust free, and I dont want to cut it.
 
rumblefish360 said:
ESPO.com (springs and things)
A 1 inch over bend is what I have used in the passed and that cleared the tire height. Your biggest concern is width. In jounce (compression of the springs and shocks) the tires should t stick out of the wheel wells.
Click to expand...
Great info rumblefish
Did you have success going 1 inch over stock springs with a 15 inch tire? I thought I may have to go 2 inches. I dont want to over kill it.
Thanks
 
Mattax said:
If you want to do it once.
Weigh the car at race weight. Get the weight on the rear wheels alone.
Remove the current springs.
Measure the free arch,
Measure the how far each compress when a heavy weight is placed on them.
>The way I do this is by standing on them after weighing myself, or whoever is the victim.
> be care full when getting off the spring, it can throw you!
Now you can calculate the spring rate of each one, and you've measured the free arch.
Depending on how beat up the spring is, the rate and free arch may be less than new. Especially the right side.
But it tells you exactly where the springs are at. So you can then select new ones and know what they will do.

One spec that can't be easily measured or figured is the spring ratio.
Look at the number of leaves, where the second leaf end is positioned under the eye, and the thickness of the main leaf and the 2nd leaf.
This gives a pretty good idea of what you have, and what to ask about when shopping.
Click to expand...
^^^^^^^^^^^^^^^^
Great stuff, this is way I joined this forum.
 
I ordered the 1 inch over bend for my ‘74 Duster which cleared a 28” tire. 275/60/15

Speak with espo directly for your exact needs and wants.
 
512Stroker said:
Good call, that's what's happening - taller tires - taller ride height.
I would normally tub the car to fit the tire size, but this is an original CA car, rust free, and I dont want to cut it.
Click to expand...

Move the rear back a touch with a spacer.
 
I think its possible with race scales to estimate the spring rate of the springs on the car. I haven't done this way, but it would be the same idea except placing jack stands on each scale and have each one supporting the axle at or next to the spring perch.
 
Another vote for ESPO. Easy to deal with and they’ll get you what you need.
 
guys..

The guy is literally jacking the car sky high with overarched springs to gain tire clearance, for the height of the tire...

Springs are EXPENSIVE!

for 10 bucks he can try the spacer and probably eliminate the problem. Maybe even be able to drop the ride height which would make new sprngs a better expenditure in the long run.
 
roccodart440 said:
guys..

The guy is literally jacking the car sky high with overarched springs to gain tire clearance, for the height of the tire...

Springs are EXPENSIVE!

for 10 bucks he can try the spacer and probably eliminate the problem. Maybe even be able to drop the ride height which would make new sprngs a better expenditure in the long run.
Click to expand...
Here's why I am replacing the springs.
- Note the funky spring helper added by a prior owner
- None stock length rear shackle
- To top it off it currently has a 4 degree positive pinion angle
IMG_20190306_143137398.jpg
IMG_20190306_143207273.jpg
 
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Remember that all springs will settle down in time. Be sure to order 6 leaf springs like a 340 car came with from the factory. It looks like this car has 318 or /6 leafs now. I have ESPO springs on all 3 of my Darts some are 15+ years old and still work well.
 
I don't know what the difference is in your car and a 65 Valiant rear wheelwell but I am sure they are different, just how different I don't know.....BUT......on my 65 I ran the 002 and 003 SS springs with the 3/4 MP offset hangers and shackles with 28/11.50/15 MT ET Streets on Centerline 15 X 9 Auto Drags. Car went mid 11s and I drove it everyday for almost four years. Does that mean I'm a keyboard mechanic?
 
512Stroker said:
Here's why I am replacing the springs.
- Note the funky spring helper added by a prior owner
- None stock length rear shackle
- To top it off it currently has a 4 degree positive pinion angle
View attachment 1715299340 View attachment 1715299341
Click to expand...

There are those that use two 003 springs, and have higher ride height, and set level .
Eye catching paint scheme < always liked the Sox/Martin colors !
 
RustyRatRod said:
I don't know what the difference is in your car and a 65 Valiant rear wheelwell but I am sure they are different, just how different I don't know.....BUT......on my 65 I ran the 002 and 003 SS springs with the 3/4 MP offset hangers and shackles with 28/11.50/15 MT ET Streets on Centerline 15 X 9 Auto Drags. Car went mid 11s and I drove it everyday for almost four years. Does that mean I'm a keyboard mechanic?
Click to expand...
No just the opposite.
That means you have real experience.
That is the kind of input I was looking for.
Thanks
 
The wheel off set to this wheel and tire combo is not really a good offset for the car. I call these GM offset, AKA, shallow. I do not have a picture handy of the huge amount of space between the tire and spring. This is a ‘71 Duster w/275/60/15 & 3500lbs. S/S springs.

On this page midway down, is my pervious Duster, a ‘74 with the 1 inch over net springs from espo. I don’t remember the tire size. It was also tall but a ‘70’s series passenger car tire. There is a little less height. IMO, the espo springs road better. Not as stiff riding. They had the car doing straight on launch.
rumblefish's Duster project
CA519E93-CA96-4211-8E21-678F18E022D0.jpeg
03151370-3F47-4B0A-B0B3-B35ECD175ACE.jpeg
C559D6AB-7BAE-4FF9-8F42-DCD48BE72732.jpeg
041A8E0C-CF46-4F1C-8AA6-D4C4CDD19335.jpeg
 
That rear shackle doesn't look right. As you mentioned it looks too long but it also looks like it is slammed against the frame unless it's an optical illusion. It need to be able to move rearward under compression forward under braking, decal and acceleration.
 
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