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I have a similar setup as yours in my 46 Ford Coupe (stock mustang II with coli over conversion). I'm sorry that I can't help you with spring rates since I can't remember the exact springs I used. It's been in service for over 20 years.

My car weighs about 3900 lbs with me and a half tank of fuel. I'm pretty sure I used the heaviest springs that I could get at the time. Seems to me that I started out with 500 lb springs, but they sagged pretty quick and started looking like yours. I think I went to 600 lb springs after that, but I notice that they might need to be replaced on the next freshening up I do on the car.

What I can tell you for sure is that removing the shocks and springs from mine is a more difficult than just unbolting them and dropping the control arm with a jack due to the deep construction of the stock stamped MII control arms. The strut rod rubber bushings will not flex enough to allow them to come out this way. I have to unbolt the struts from the lower control arm to get enough travel. I seem to remember having to break the lower ball joint loose, too, but it's been a loooong time since I had to pull them out.

You may have a tough time getting good suspension travel and keeping the ride height that you have now without going to dropped spindles. you can adjust the control arms for good travel and still get 2" lower ride height. Just a suggestion.

Also, I have looked at several stock MII's (the actual Ford car) and they all have the lower control arms running slightly downhill toward the tire when viewed from the front. This is because, on the stock stamped CA's, the center of the pivot bushing is not directly in line with the center of the ball joint ball when the CA is level. Having "level" control arms means having a line drawn though these pivot points level. Tubular CA's are not made like this and they will be level to the eye.
 

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What you have is an early aftermarket cross member kit. A stock crossmember has a rolled edge to strengthen the spring tower. Also the tie rod ends have been lengthened to accommodate a longer spread distance from one side of the frame to the other. The lower control arm should be angled down from the pivot bolt. When it is level, you are 3/4 of the way through the stock travel.
 

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To date I have installed over 50 stock mustang 2 cross members . The early ones have a T shaped bolt that drops down into the cross member and turns to hold the upper control arm, the later ones have a river head bolt that is installed from the bottom of the spring tower. Also there are 2 stock widths on the crossmembers , measuring the spread of the lower control arm pivots
 

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Discussion Starter · #28 ·
What you have is an early aftermarket cross member kit. A stock crossmember has a rolled edge to strengthen the spring tower. Also the tie rod ends have been lengthened to accommodate a longer spread distance from one side of the frame to the other. The lower control arm should be angled down from the pivot bolt. When it is level, you are 3/4 of the way through the stock travel.
Makes since that this is an early crossmember since the rod was built 15-20 years ago. I'll keep the control arm angle in mind when swapping the springs, not sure what the actual angle is since the car is so low and has been in my small garage since I bought it. All I have is the one picture to go by and the angle it was taken at could affect the perception.
 

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Start with the given. From the center of the spindle to the floor is about 12 inches, look at the car and see what the tire/ wheel clearance is to the fender opening. You can go with a longer spring/shock setup and then put a set of dropped spindles to bring the ride height down. Ideally the lower control arm pivot bolt should be 12in To put the control arm in the proper place.
From the picture, there’s a lot of work to be done. It is almost worth it to start over with a newer cross member setup. The first attempts at cross member kits were not that good. That’s why I stuck with the oem cross member. The first one I did was 1976. 1936 Plymouth sedan. 13 years And 147k miles. Sold it to a friend who is Still driving it.
 

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Discussion Starter · #30 ·
Start with the given. From the center of the spindle to the floor is about 12 inches, look at the car and see what the tire/ wheel clearance is to the fender opening. You can go with a longer spring/shock setup and then put a set of dropped spindles to bring the ride height down. Ideally the lower control arm pivot bolt should be 12in To put the control arm in the proper place.
From the picture, there’s a lot of work to be done. It is almost worth it to start over with a newer cross member setup. The first attempts at cross member kits were not that good. That’s why I stuck with the oem cross member. The first one I did was 1976. 1936 Plymouth sedan. 13 years And 147k miles. Sold it to a friend who is Still driving it.
Today I was able to drive the car a much longer distance. Rides much better than I thought- the roughness was flat spots in the tires that went away after a while. Did bottom out on a large speed bump, but does have some travel. Still a bit stiff and could use some improvement, but not bad and perfectly acceptable for a street rod. The lower A arms, looking under the front for the first time, are exactly parallel with the pavement. I believe it was you that posted they needed to go slightly downhill from inside to outside pivot?

Brakes are another story. The stock (I assume) Mustang II brakes with under floor power booster are very weak. They will bring the car to a stop, but can't skid a tire and are reminiscent of mechanical brakes. If anyone is using similar brakes on a car of similar weight with better results, let me know. Speaking of weight, I tried the Youtube "posterboard" method and came up with a whopping 5400 pounds. That can't be right- original curb weight was supposed to be 4300 and this car has a small block, not a V-12. Should be closer to 4000. I'll take it to the scale at the county landfill.
 

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As for brakes. If you’re running a GM rear end go with 69to 72 Camaro rotors and calipers Use the inner and outer mustang bearings with a National oil seal 50409. if A Ford rear use Granada rotors. They willing handle the breaking chores. Brake caliper brackets are available from several suppliers
 

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Discussion Starter · #32 ·
So can someone tell me what would happen if I simply adjusted the coil over adjustment nuts downward, say an inch? Obviously suspension travel increases, but what happens to ride height and lower control arm position? Right now the bottom of the stock arms are exactly parallel with the pavement.
 

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Discussion Starter · #33 ·
I have a similar setup as yours in my 46 Ford Coupe (stock mustang II with coli over conversion). I'm sorry that I can't help you with spring rates since I can't remember the exact springs I used. It's been in service for over 20 years.

My car weighs about 3900 lbs with me and a half tank of fuel. I'm pretty sure I used the heaviest springs that I could get at the time. Seems to me that I started out with 500 lb springs, but they sagged pretty quick and started looking like yours. I think I went to 600 lb springs after that, but I notice that they might need to be replaced on the next freshening up I do on the car.

What I can tell you for sure is that removing the shocks and springs from mine is a more difficult than just unbolting them and dropping the control arm with a jack due to the deep construction of the stock stamped MII control arms. The strut rod rubber bushings will not flex enough to allow them to come out this way. I have to unbolt the struts from the lower control arm to get enough travel. I seem to remember having to break the lower ball joint loose, too, but it's been a loooong time since I had to pull them out.

You may have a tough time getting good suspension travel and keeping the ride height that you have now without going to dropped spindles. you can adjust the control arms for good travel and still get 2" lower ride height. Just a suggestion.

Also, I have looked at several stock MII's (the actual Ford car) and they all have the lower control arms running slightly downhill toward the tire when viewed from the front. This is because, on the stock stamped CA's, the center of the pivot bushing is not directly in line with the center of the ball joint ball when the CA is level. Having "level" control arms means having a line drawn though these pivot points level. Tubular CA's are not made like this and they will be level to the eye.
Very useful info. Theoretically the weight of my car should be very close to yours, but will find a scale to make sure. One my car, the bottom of the stamped steel arms is parallel to the ground.
 

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So can someone tell me what would happen if I simply adjusted the coil over adjustment nuts downward, say an inch? Obviously suspension travel increases, but what happens to ride height and lower control arm position? Right now the bottom of the stock arms are exactly parallel with the pavement.
With the adjusting nut on the bottom, all that will do is lower the ride height....it won't change ride stiffness at all. To change ride quality, you've got to change the spring rate.
 

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Discussion Starter · #35 ·
With the adjusting nut on the bottom, all that will do is lower the ride height....it won't change ride stiffness at all. To change ride quality, you've got to change the spring rate.
So adjusting the nut downward will lower the height? I assumed the reason they were adjusted so far upward was to get the car down on the ground. Also, it seems to me like the spring characteristics will change as the nut is adjusted down - coils will open up, suspension will have a lot more travel, and ride should improve. A compressed spring with little travel should have a rougher ride.
 

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Adjusting the nut downward will lower the ride height. It will not change ride characteristics. If you don't believe us, try it and you'll learn for yourself. A number of people posted "you need a stiffer spring, higher load rating, or a higher spring rate". They all mean the same thing. You have too much weight up front for the springs you have. CHANGE THE SPRINGS.
 

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So adjusting the nut downward will lower the height? I assumed the reason they were adjusted so far upward was to get the car down on the ground. Also, it seems to me like the spring characteristics will change as the nut is adjusted down - coils will open up, suspension will have a lot more travel, and ride should improve. A compressed spring with little travel should have a rougher ride.
It doesn't work like that exactly.
Coil spring rate is dependent on three things. The wire diameter, the width of the spring and the number of coils.
On coil overs, you aren't changing any of the above unless you run the adjuster up to the point some coils are touching. That reduces the number of active coils and makes the spring stiffer but your lose the travel to soften the ride. Assuming they are not touching, or coil bound as we call it, all your doing is adjusting the relative position of the spring to the frame of the car. Basically adjusting the ride height and that's it.
If the car weighs 4000lbs, the front weighs 2000lbs and each corner weighs 500lbs, than 250lb spring would compress 2". Moving the nut up or down doesn't change the amount of weight the spring has too hold up. In this case it's 500lbs.
A longer 250lb spring lowers the nut but still compresses 2". A short 250lbs spring raises the nut but still compresses 2".
The idea is too find the weight the spring has to hold up, selecting a rate that holds up the car and is still long enough to put the adjuster nut somewhere in the range of it's adjustable range.
In your case, the spring is too short if you want to keep the ride how it is(coil binding), it's too soft and too short if you want a stiffer ride( coil binding and won't hold up the car).
So now you have to decide what your want. A softer or stiffer ride? The same ride quality but not bottoming out?
If it's just ride height and you're okay with the quality then you need 3-4inch longer spring in the same rate so the adjuster nut can have more upward travel to set the ride height where you want it.
 

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Discussion Starter · #38 ·
So now you have to decide what your want. A softer or stiffer ride? The same ride quality but not bottoming out?
If it's just ride height and you're okay with the quality then you need 3-4inch longer spring in the same rate so the adjuster nut can have more upward travel to set the ride height where you want it.

As it turned out, my problem with the ride was mainly flat spots on the tires from 15 years storage. After driving a mile or so and getting used to the fact that it doesn't ride like a stock '48 Lincoln (a mobile sofa), I'm OK with the ride. And the ride height is perfect. So I guess what I have to decide is whether the suspension has adequate travel, and I'd say it's an inch or two short of that. And if I change the springs, I might as well soften the ride a notch or two. The trick is figuring out what spring to buy- I don't want to do three trial and error tear down and rebuilds of the suspension. While I'm at it I'll replace the pathetic 9" brakes with 11".
 

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As it turned out, my problem with the ride was mainly flat spots on the tires from 15 years storage. After driving a mile or so and getting used to the fact that it doesn't ride like a stock '48 Lincoln (a mobile sofa), I'm OK with the ride. And the ride height is perfect. So I guess what I have to decide is whether the suspension has adequate travel, and I'd say it's an inch or two short of that. And if I change the springs, I might as well soften the ride a notch or two. The trick is figuring out what spring to buy- I don't want to do three trial and error tear down and rebuilds of the suspension. While I'm at it I'll replace the pathetic 9" brakes with 11".
This is the brake kit I used, it's a true bolt on. Only install tip is to sand the paint some from the outside of the replacement oil seals so they install easier and don't distort, read the reviews on the website. They also offer the kit with a Ford bolt pattern.
https://www.speedwaymotors.com/Must...ront-Disc-Brake-Kit-5-x-4-3-4-GM-BP,2007.html
 

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Discussion Starter · #40 ·
This is the brake kit I used, it's a true bolt on. Only install tip is to sand the paint some from the outside of the replacement oil seals so they install easier and don't distort, read the reviews on the website. They also offer the kit with a Ford bolt pattern.
https://www.speedwaymotors.com/Must...ront-Disc-Brake-Kit-5-x-4-3-4-GM-BP,2007.html
Thanks for posting that, without a recommendation from someone buying a kit is just a shot in the dark. Price is great too!
 
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