Replacement Lowering/Performance Coil Spring Confusion

[87CrownVic]

I've been reading through the suspension info and comparing spring rates and heights available in different brands and I'm really starting to get confused. I'm ready to order some stiffer lowering springs for the 79 LTD-S 2 door now that we got the new rock auto code.

Plain and simple: I am looking for an approx. 2" drop front spring with a rate between 1,000 and 1,100 and an approx. 2" drop rear spring with a rate between 200 and 225.

If anyone is able to identify what I am looking for in a Moog spring (or any other brand that I can cross reference for that matter), I would seriously appreciate it. I've just been sitting here with a piece of paper with about 25 part numbers on it going back and forth for a week now, getting seriously confused.

[87CrownVic]

What do you guys think about getting a standard replacement spring and precision cutting a measured amount off the appropriate end? I cant find what I'm looking for, and I figure this will bring me reasonably close the the higher spring rate I want as well.

[gadget73]

Stock replacement springs will be somewhere in the 380 in/lb range. Cutting them makes them stiffer, but I don't really know if it makes them enough stiffer to handle a 2" drop without bouncing you off the stops way too much. GMGT's Vic has I think the 1" lowering springs, and it rides a hell of a lot better than I'd have ever expected it to, and it does not bounce off the stops. Personally I'd go with the higher rate springs, and if they're taller than you'd like, trim them down.

[pstrbrc]

Using the speedway springs on the front, then cutting them down half a coil would work on the front. But the rears use a pigtail at both the top and bottom to locate them. Cutting off any of this would mean the spring wouldn't fit in the spring seat. (This is a bad thing). These guys can make you springs to your specs (what car, what ride height, what spring rate) for about $50 a spring. Not sure there are too many other choices for the rear.

[gadget73]

50 bucks a spring for custom is cheap. Off the shelf stock replacements are about 75 for the pair.

[87CrownVic]

Using the speedway springs on the front, then cutting them down half a coil would work on the front. But the rears use a pigtail at both the top and bottom to locate them. Cutting off any of this would mean the spring wouldn't fit in the spring seat. (This is a bad thing). These guys can make you springs to your specs (what car, what ride height, what spring rate) for about $50 a spring. Not sure there are too many other choices for the rear.

Yes, I was thinking the rears would be extremely hard to find a replacement for that didn't rake the vehicle. $50 a spring is extremely affordable. I will look into this and report my findings. I talked to a local spring company about what I was looking for and they were well over double that.

[87CrownVic]

Am I way off on my front spring rate approximation? I had a couple establishments tell me that a 1000lb spring rate is beyond excessive for the front of my vechicle, but speedway has the replacement 1" drop springs available in 725 up to well over 1200...

I talked to Coil Spring Specialties today and I got quoted at $176.48 for the fronts and $160.20 for the rears. The fabrication tech is going to call me back tomorrow and discuss some specifics that might bring the price down slightly, but not very close to $50.00 a spring. pstrbrc, did you talk to anyone in particular or deal with them in the past?

[pstrbrc]

Am I way off on my front spring rate approximation? I had a couple establishments tell me that a 1000lb spring rate is beyond excessive for the front of my vechicle, but speedway has the replacement 1" drop springs available in 725 up to well over 1200...

I talked to Coil Spring Specialties today and I got quoted at $176.48 for the fronts and $160.20 for the rears. The fabrication tech is going to call me back tomorrow and discuss some specifics that might bring the price down slightly, but not very close to $50.00 a spring. pstrbrc, did you talk to anyone in particular or deal with them in the past?

OOps! OK, three things. It was, I don't know, 15 years ago that I bought springs from them, and it was $60 apiece. (I found my records.)
Sorry 'bout that. Didn't mean to misinform. Spring steel costs a WHOLE bunch more today!

About the front spring rate. My ballpark math sez that if you lower a box 2", yer gonna need a minimum of 825# springs to keep it off the bumper stops. 850# seems like a good target. But, yes, it's gonna ride stiff-legged. And looking at how low the front crossmember is, I'm not sure cutting down the bumper stops to get more suspension travel is an option. Maybe no more than 1/2". Then you would need shorter shocks. '70-'80 Dodge pickup shocks have about 3/8" shorter compressed height. Then you could go with about 750# springs, or about what PI springs are rated. Only thing about the Dodge shocks are, the shock mounting bolts on the lower a-arm are about 1/2" further apart, so you'd have to do some grinding on the lower shock mount to make them fit panther lower arms.

[87CrownVic]

I figured it might have been awhile, that makes sense. I just gave them the OEM spring specifications and told them I want a spring with a 2" lower trim height (loaded spring height), and 30% higher spring rate. They did the math and sent it to fabrication/production. Thanks for the shock info, I've been doing some research involving extended length, mounting style & dimensions, and load capacity. I'll let everyone know when I come to a conclusion.

[87CrownVic]

I found a shock absorber for the front and possibley the rear. There is a Monroe Reflex available in the same mounting configuration and 2" shorter, part# 911137. There is also a MonroeMatic (OEM super-squish) in the same configuration, part# 32318.

The rear is also available in the same mounting configuration and 2" shorter, but it is a MonroeMatic as well. It is part# 33136.

The Reflex used to be made for heavy-duty car applications, but now just for light-duty trucks. It has stiffer valving and should control the harshness upfront a little better. I'm trying to crossreference the rear shock to find a more suitable replacement, but I haven't found anything online or through the interchange yet. I also changed the final specs on the springs before they started making them. I found decreasing the spring rate to 25% over stock from 30% should help with unloading the rear end when I eventually mount drag shocks on the vehicle. I also decreased the rear spring drop from 2" up to 1 1/2" to allow more room for 275/60/15's.

[1980c10]

rear shock will be fine the stock length. with the stock ride height they are all the way stretched out anyway, so going down 2'' would prolly put them where they are supposed to be

[Darkmerc]

I found a shock absorber for the front and possibley the rear. There is a Monroe Reflex available in the same mounting configuration and 2" shorter, part# 911137. There is also a MonroeMatic (OEM super-squish) in the same configuration, part# 32318.

The rear is also available in the same mounting configuration and 2" shorter, but it is a MonroeMatic as well. It is part# 33136.

The Reflex used to be made for heavy-duty car applications, but now just for light-duty trucks. It has stiffer valving and should control the harshness upfront a little better. I'm trying to crossreference the rear shock to find a more suitable replacement, but I haven't found anything online or through the interchange yet. I also changed the final specs on the springs before they started making them. I found decreasing the spring rate to 25% over stock from 30% should help with unloading the rear end when I eventually mount drag shocks on the vehicle. I also decreased the rear spring drop from 2" up to 1 1/2" to allow more room for 275/60/15's.

Thank you sir for your research.

[87CrownVic]

I found a rear sensatrac in the same configuration that is 1 1/2 inches shorter (will work perfectly) in a Monroe Senstrac. I prefer the Sensatrac over the Monroematic and will be using it. Monroe Sensatra part# 5839.

BTW, does anyone have information on the OEM spring rate for the front and rear springs on a 79 LTD-S two door? The new spring rates are @ 490 front, 140 rear which still seems incredibley soft. That is a 30% increase in front spring rate and 25% increase in rear spring rate according to Coil Spring Specialties. They also called back to tell me my springs will be more expensive and will be taking longer (yay). I'm not as confident as I'd like to be that these guys have all their facts straight, but I guess we'll find out...

[87CrownVic]

I recieved my lowering springs today. $350 later. I decided to switch my shock choices too. Another option is KYB, which I found a much more desirable front and rear combination from. Fronts will be KYB Monomax #565049, rears will by KYB Gas-A-Just #KG5519. They're more expensive than the Monroe's, but I definately feel they will be worth it. I just have to get the Energy Suspension 43150 kit, sway bar end links, and blast/zinc coat the rear bar & control arm hardware. Maybe I can get it done before my brother's wedding next weekend. :no:

[83countrysquire]

i want to see how this looks when your done cause I wanted a 2" drop in front and like a 1 1/2 in rear to have a rake look