620 Coil Spring Install

The stock ride height of any car leaves a little to be desired in my opinion. I am not a big fan of showing off my inner fender wells. This was one of the first customizations I did to my car due to the fact that it was very simple and very cheap. I bought the Grab-a-Trak 620 front coil springs on eBay for $59 which was slightly less than ordering directly though Mustangs Plus.

These are really nice springs as they come black powder coated, so they will retain a nice finish (mine still look new after 3+ years of use). See Fig 1 for a comparison between my stock springs and the 620's. I went ahead and installed them stock since they were supposed to provide a 1" drop compared to the stock springs. I went ahead and bought an internal style spring compressor, because I knew I would be taking these off again someday for a disc conversion. It turns out I have probably taken the springs off like 4 or 5 times. You can get a good spring compressor like this one at Northern Tools for around $30.

On a Mustang you will run into an issue with the large screw in the coil spring compressor being too long to allow for proper compression of the spring to get it out of the car. The spring will drill right down into the spring perch long before it is compressed enough. My solution was to stock up on heavy duty washers at the hardware store instead of cutting the shaft of the tool (you can see an example of this in Fig 2). Additionally, when installing the new 620's with the powder coating you may want to take an old bicycle tire tube and cut four short strips to place over the arms of the spring compressor. This will help protect the surface of the coil when compressing so you don't have any scratching or chipping.

Now for the post installation reports..... As you can see from Fig 3 the initial installation didn't go as planned. I wanted a lowered Mustang, not an off-road Mustang! I removed the coils and called Mustangs Plus immediately. It turns out they had sent me the wrong springs on accident. The ones I had were for a big block 67-70 so they were much stiffer than the 620's. They offered to send me the correct ones, but after discussion we decided that for the ride height I wanted I would have to cut the 620's as well. I decided to keep the ones I had and cut them with a hacksaw. It was alot of work and a few blades to make it through the thick coils, but it could be done in my garage and I had read it isn't a good idea to put too much heat to the coils when cutting (i.e. a torch).

It is generally recommended to cut of 1/4 of a coil at a time. Based on the rediculous height of my car and from what I read I decided to start with 1 full coil (See Fig 4). Luckily the full coil wasn't too much, and it put the car basically at a ride height that I liked (See Fig 5). After cutting off a full coil there is very little compression required to install the spring into the uncompressed suspension (you maybe have to compress it 1/2 to 1" at the most). This makes removal and installation a snap for future upgrades.

Two other things of note related to my experience with this mod (may be slightly different on your car). One is that many people suggest that your springs will settle as much as 1" after driving the car a bit. I have had mine on my car for over 3 years and have notice no settling as of yet. The other thing is there is a misconception among some that the 1" Shelby drop (i.e. relocating the upper control arm down by 1") will in turn lower the car. I did the Shelby drop as part of my Granada swap after I installed and cut these springs. I didn't see any noticable change in the ride height after this as well. I had read many places from experienced Mustang customizers that this didn't affect ride height. That is why I didn't hesitate to install the springs and set my desired ride height prior to doing the Shelby drop (which made more sense to do with the Granada swap since I would have to remove the spindles for this anyway).

Project Pictures

Fig 1 - Comparison of the stock springs with the new 620's

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Fig 2 - Slightly modified coil spring compressor

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Fig 3 - Pic of my off-road Mustang

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Fig 4 - Pic of the coil after cutting a full coil

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Fig 5 - Much better ride height

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