I'm finally getting ready to order suspension parts but I keep running into a few questions that I'm looking for answers for before I buy anything. I have a budget I'm trying to stay within and want to optimize which components I should splurge on and which ones I should cut back on. My goal is to build a suspension that'll handle really well on the street while still being enjoyable to drive. Stiffness isn't a problem. I hate floaty suspensions, body roll, and too much understeer. Btw I currently have installed opentracker roller bearing control arms and spring perches up front.
Leaf springs - I was going to get the maier racing 165lb leafs but now I'm considering the grab-a-trak 4.5 mid eye leafs instead since they cost less and seem to get positive reviews. How are the grab-a-traks with wheel hop? Would I be making a mistake by not getting the maier leafs? If I get the grab-a-trak leaf springs then that could enable me to splurge a bit more on shocks.
Front springs - I have 480lb springs in there now but I'm wondering if I should pull them out and swap in 620lb springs instead. How do the two springs compare on the street? Will the 480 springs be too soft?
Shocks - I was considering kyb gas-a-just shocks since they are so cheap. The other shocks I'm considering are bilstein sport valves shocks. These might be too stiff with 480lb front springs though. Would 480lb springs and bilstein street shocks be a better combo than the gas-a-just shocks or bilstein sport shocks? Would it be worthwhile to run 620lb springs and bilstein sport shocks instead?
Leaf spring bushings - I've read that it's best to just leave the stock rubber bushings in. Some people use polyurethane bushings in the front and rubber in the rear. I'm considering using a panhard bar. Should I stick with rubber bushings in the front and rear eyes if using a panhard bar?
What year mustang do you have?
Did you perform the arning drop?
Get the street or track strut rods, 620 grab a track springs.
Avoid the KYB Gas a just like the plague! Bilsteins are far better. 1" sway bar also.
People have different experiences, but I have found that having NO poly joints at all in the front to be preferable to me. Del Alum and spherical bearings for me.
I have a 65 coupe. I did perform the arming/Shelby drop.
620 springs and bilstein sports sound like a good combo to run. Do the 620 grab-a-track springs drop the car 1 inch?
Will running a 1 inch sway bar introduce more under steer ?
Springs are hit and miss as far as actually lowering the car. I would plan on installing and removing and cutting a time or two.
You will have to try the bar and see really. Generally the 1" work for most people.
There is a 15/16" version also....
The 4.5 leaf is a very good spring, it's rated at 175lbs. We remove the band clamps and add two leaf spring clamps to the front half of each leaf, one at the front of the half leaf and the other half way between the front spring eye and the housing. On a performance leaf spring suspension, you want all the spring action to happen on the rear half, the front half should work like a swing arm.
The 620 stands for the size of the coil at .620" not the spring rate. The rate of the coil is 560lb so you wouldn't be going up all that much by changing springs. It wouldn't be a big change from the drivers seat.
If you wanted to increase the spring rate of the springs you have now, you can move the perch 1" closer to the ball joint. We've been doing that for years and it works well to change to a more favorable motion ratio. The 1" perch move will raise the car 1/2" and increase the spring rate about 100lbs. Here is an on line photo of the move done to one of our control arms. The 1/2" rise can be offset by cutting 1/4 coil off. This mod is nice because it's free and easy to do.
If your budget can handle it, go with the Bilstien shocks. The sport valve won't be too stiff with the roller parts you have and you'l have a better handling car with improved ride quality.
You don't want poly in the front of the leaf spring, it's too harsh and binding IMO. Poly works good in the rear though it still binds some. The $99 racing poly shackle kit works well for the rear. Rubber front - poly rear is our rule for the leaf springs.
Another option is to go with the Delalum kit from Global West. That will work like the roller parts in the front because it's a greaseable bushing kit for the front and rear of the leaf springs and lets them move without bind. The kit will also help keep the rear end centered under the car similar to a panhard bar because the bushings don't flex like rubber or poly. A panhard bar is a nice upgrade too but I would do the Delalum kit first to get the leafs to move properly without bind from the rubber/poly bushings.
The 4.5 leaf is a very good spring, it's rated at 175lbs. We remove the band clamps and add two leaf spring clamps to the front half of each leaf, one at the front of the half leaf and the other half way between the front spring eye and the housing. On a performance leaf spring suspension, you want all the spring action to happen on the rear half, the front half should work like a swing arm.
The 620 stands for the size of the coil at .620" not the spring rate. The rate of the coil is 560lb so you wouldn't be going up all that much by changing springs. It wouldn't be a big change from the drivers seat.
If you wanted to increase the spring rate of the springs you have now, you can move the perch 1" closer to the ball joint. We've been doing that for years and it works well to change to a more favorable motion ratio. The 1" perch move will raise the car 1/2" and increase the spring rate about 100lbs. Here is an on line photo of the move done to one of our control arms. The 1/2" rise can be offset by cutting 1/4 coil off. This mod is nice because it's free and easy to do.
If your budget can handle it, go with the Bilstien shocks. The sport valve won't be too stiff with the roller parts you have and you'l have a better handling car with improved ride quality.
You don't want poly in the front of the leaf spring, it's too harsh and binding IMO. Poly works good in the rear though it still binds some. The $99 racing poly shackle kit works well for the rear. Rubber front - poly rear is our rule for the leaf springs.
Another option is to go with the Delalum kit from Global West. That will work like the roller parts in the front because it's a greaseable bushing kit for the front and rear of the leaf springs and lets them move without bind. The kit will also help keep the rear end centered under the car similar to a panhard bar because the bushings don't flex like rubber or poly. A panhard bar is a nice upgrade too but I would do the Delalum kit first to get the leafs to move properly without bind from the rubber/poly bushings.
Thank you for all the information. I did not realize that about the 620 springs. I will stick with my 480lb springs for now and see how I like them with bilstein shocks.
Are the 4.5 leaf mid eye leaf springs you sell the same as the grab a trak leaf springs or do yours differ?
I realize that in your application you want to come down an inch but since everyone is on the topic. If I want to replace my sagging stock rear leaf springs and get my 66 coupe back to stock height, what leaf should I be looking at getting? Is it the 4 leaf, the 5 leaf or this 4.5 leaf I've been reading about here? Thanks for the info regardless!
-Dylan
__________________
1966 Emberglo Coupe
289 with automatic C-4
Deluxe Pony Interior
Dylan I could be wrong but in the research I've been doing I believe the mid eye and reverse eye leaf springs lower the car and the standard eye (for lack of an official term) is stock ride height. Adding more leafs will increase the stiffness. 4.5 should be stiffer than 4, 5 leafs should be stiffer than 4.5.
I have been trying to figure out what rear suspension modifications would be best for my 66 coupe. I want slalom not drag strip. It is nearing the reassembly stage and I need to get this right. I am going to keep the rear leaf set up.
What I am finding is that a read stab bar is not a good option. Traction bars are not a good option.
The cornering enhancements for a performance leaf set up are
1) bilstein sport valve shocks (front and rear assumably),
2) the Delalum kit from Global West" and a
3) 4.5 or 5 leaf spring clipped on the front half to lessen spring response?
For my '68, I actually went with Global West upper/lower control arms with the Maier 600# front springs and their 160# race leafs. I ended up with Koni shocks with a 1 1/8" front sway bar and a 3/4" rear. I do have a stroked Windsor and a TKO-600 but I love how it rides and I drive it almost every day. I actually have the KYB's on my '73 Mach-1. They're fine. I would have gone with Bilstiens but the price was right and there were other things I had to get.
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Suspension questions
