• Hello there guest and Welcome to The #1 Classic Mustang forum!
    To gain full access you must Register. Registration is free and it takes only a few moments to complete.
    Already a member? Login here then!

Cutting springs to lower vehicle - your experience/advice?

M

miketyler

Member
I want to lower the front of my car 1-2 inches and I would like to experiment with my springs. From what I have seen, they are cheap so if I get it wrong, I'll replace them and start over. My car is a 70 Mach with AC, 351c and will have AOD trans. Battery will stay in front. Have relocated UCA for Shelby drop.

How much spring should I lose on the original stock springs? I was thinking one full coil with the cut directly below the factory end coil. I appreciate your advice and experiences here

 
One full coil should get you where you want to be. I myself would just put a 620 spring with a one inch drop instead of cutting the spring. Rich.
 
Thanks for responding Rich - I thought I would give this a shot first. The 620's are always an option. I need to get the car back on the ground today and needed advice on the decision on how much to lose.

After the cut, I will lose the 1-2" straight protrusion that the original spring had. I understand about dressing the cut to a smooth 90* so it sits on the saddle spring stop correctly but without the protrusion, will it miss the stop or is there some other mod needed to make sure it has proper mating?


RIP John Pro
 
We cut a lot of springs around here. Just make sure you measure well and cut them both the same. When I'm lowering a car a lot like you are, I'll make index marks every 1/4 coil for the first two rounds so I don't mess up. The index marks keep you posted on how equal the cutting is on each spring.
 
Thanks for posting, am not sure I understand; so you recommend cutting 1/4 at a time and installing after each cut to ck drop?

The engine is out of the car (and so is everything else). I have never cut springs before but I assumed if both sat level previous that as long as I take off the same amount on each, and made sure finished height was the same I was probably good to go?

I really value the expertise here. I know its a bit of a dice roll since I have dropped the UCA.
 
Yes, if the car sat level, it most likely will sit level after cutting. Most cut a quarter to half coil at a time. You will not know how the car will sit until all the weight is on it. Remember, it is easier to cut a second time than try to add the cut off section back in. Also, the spring rate gets stiffer as you shorten it.
 
On most cars I cut 1/4 coil at a time but if I'm sure I want to lower the car an inch or more, I'll cut off more. For a 2" drop, you can take a full coil off with the first cut, then go slower after that. The index marks are just to keep track of where you are on the cutting.
 
I only cut a quarter off mine and it's really too low but it looks good. I also have an iron head 429 aiding the compression of the springs. Also when I put the ORP roller perches it dropped some more.

After the cut, I will lose the 1-2" straight protrusion that the original spring had. I understand about dressing the cut to a smooth 90* so it sits on the saddle spring stop correctly but without the protrusion, will it miss the stop or is there some other mod needed to make sure it has proper mating?
Click to expand...

As to your other concern, cut the coil from the bottom, the perch is made to seat the spring that's not flat.
 
Great - here is a pic of the car sitting on a slightly inclined drive when I first got it. Engine and all was in the car at time and those turb wheels are are 14". I plan to put 17" wheels on it and would like the top of wheel opening to be at or just above the top of the rim. This may not be practical since I will be running long tube headers but this is my target.
 
As to your other concern, cut the coil from the bottom, the perch is made to seat the spring that's not flat.
Click to expand...

Understood, thats where I have intended to make the cut all along. The question was regarding the protrusion on factory springs. My pic I took is of the bottom of the srpings and I noticed there is about 1-1.5" that is "unwound". I thought this was for proper mate position with spring stop on the inboard side of perch.
 
here is mine with just a 1/4 cut off the stock springs and ORP perches, mine sit fine in the saddle
 
"miketyler" said:
The engine is out of the car (and so is everything else).
Click to expand...

You might want to wait to cut your springs. I think it's best to cut and test fit springs on a completely assembled car (installed engine, trans, front fenders, etc). If the car is disassembled, you won't know how it's going to sit until it's reassembled.
 
here is mine with just a 1/4 cut off the stock springs and ORP perches, mine sit fine in the saddle
Click to expand...

Great, I am probably thinking too much on this. I dont know where you were at before but from the pic, it looks like you got a substantial drop for only .25 coil loss? With my car being a 70, are our springs/cars similar enough for comparison?

You might want to wait to cut your springs. I think it's best to cut and test fit springs on a completely assembled car (installed engine, trans, front fenders, etc). If the car is disassembled, you won't know how it's going to sit until it's reassembled.
Click to expand...

Agreed but I wanted to at least take a shot at this while I have it apart now. I may lean towards .5 coil now though and see where it sits once its loaded and settled in.
 
"miketyler" said:
Great, I am probably thinking too much on this. I dont know where you were at before but from the pic, it looks like you got a substantial drop for only .25 coil loss? With my car being a 70, are our springs/cars similar enough for comparison?
Click to expand...
I don't know how the 67-70 compare but I'm guessing very close. Here is with the 429 but no mods to the suspension. Stock coil, spring perches etc. Now I have the coils cut (just a 1/4 of a coil), the ORP perches and the 1" Arning/Shelby drop on the UCA. All combined it lowered the car quite a bit, I probably didn't need to cut the coils at all.
72_07_10_08_9_02_19.jpg

index.php
 
Last edited by a moderator:
67 and 70 OEM front springs are the same I assume? What do you guesstimate the difference in weight to be from a 428 to my 351c? Also, any drop running the ORP perches?
 
351C should be ~550 and the FE is about the same (560).

I did get a slight drop with the ORP perches, I didn't measure but it's lower cuz now my tires rub and before the swap they didn't.
 
It may not have been a drop with the perches, just more freedom to move in the full range of the suspension causing the rubbing.
 
Sounds feasible. I settled on .5 coil cut, and as I anticipated, with the spring centered in the perch the end coil doesn't have the 100% positive mate with the spring stop. Do I even worry about this? Was going to try and bend the spring stop on the perch for a better mate but does this really matter? With weight on them, the springs probably have little rotative affect?
 
Was an easy matter to adjust the spring stop to better mate with the spring. I think I worry too much. :scar

After measuring several times then making the cut I thought I was golden but one spring was 3/16" inch taller than the other when measured to the top flat of the spring. I removed an additional 1/4" of coil and they now both measure the same. Maybe I'm splitting hairs?

This makes me really appreciate the e-body Cudas and Challengers with their torsion rod suspension. They are completely adjustable with much less effort than the Mustang. This is great learning for me, I appreciate all the feedback.

:dh
 
You must log in or register to reply here.
Back
Top