Thanks!  I will use the Mustangs Plus "stock" replacement then!

The important question here before many of your questions are answered is what do you plan on using the car for??  You build a daily driver way differently than you build a circle track car.  So what is your planed use??

Unless you are building a 100% track only car IMHO 620 springs are to stiff, then when you cut the coil they will only get stiffer.  Part of a car that handles well is getting the correct combination of parts then allowing them to move as designed for the best handling AND ride quality.

Let us know how you want to drive the car and we will be able to give you a better idea what parts you should use.

Check out my Webpage on the UCA drop it will give you lots of good info.  I also recommend Suspension 101 from my web page.  Here is the UCA drop alignment specs I send when I sell a template kit.Please align to these specs “1960-1966 Mustang and Falcon Performance Alignment with or without UCA drop”.  

These specifications are in order of importance.
1.  NO more than .25 degrees difference between driver’s side and passenger’s side.

2. +2.0  to +3.5 degrees caster.  
NOTE: for cars with Adjustable strut rods.  Please attain as much caster as possible using the shims (at least 1.5 to 2.0 degrees), and then use the adjustable strut rods  to increase the caster and make the sides the same.  Also, please note that the caster difference between the driver’s side and passenger’s side needs to have no more .25 degrees difference prior to the adjustment of the strut rods.

3.  -.5 to 0 degrees camber.  No positive camber, please.  There is no problem having a slight variation from driver’s side to passenger’s side to account for the crown in the road.

4.    1/16" to 1/8” toe in

If you run into any problems attaining these specs, please call me (your phone number here).
 

The three bears...  Too soft, too hard, just right.
Everything is relative.

The Mustang Plus shocks are way too soft for my taste.  KYB Gas-A-Just are too stiff.  Regular KYB's are OK, and Bilsteins are great.  That from many years of trying different things on my car.  Your taste may vary!

The Dr Gas progressive motorsports front progressive front springs will give you a great ride.  I have converted my car from the M+ 620# springs and it made a huge difference in ride quality.  They have two versions, a street and a track version.  I have used both, and the track version is not stiff at all, but gives alot better feel, with less rise on hard acceleration.  These springs do not experience continuous sag as the M+ springs do.  And you do not need to cut them to get the perfect ride height.  Al McGee just put a set of the street version progressives on his fastback with Shelby drop.  They fit awesome.  Have not heard hos latest ride report.  Whaddayasay, Al?

Rear springs from Mustang + are good and I prefer the reverse eye to get the right stance with the front spring changes you are considering.  Having reverse eye springs on your car also has an unrelated advantage.  You will now have a rear framerail that you can put a jackstand on when you lift the car up to work on it.  With standard eye springs, the springs keep the jackstand from being able to get to the frame rail.

Some of the guys are into relocating the spring perches outward.  Then also including roller bearing perches.  I really don't see why you would need roller perches (for that combination) since the bushing will rotate LESS than stock being farther outboard, plus if you don't care the spring is sitting crooked in the top spring mount, why would you care about the bottom?  I do have Opentracker perches on my car, but actually prefer the little bit of cushion and less noice of a stock original bushing.  Unfortunately all you can get other than roller perches right now are Taiwan reproductions.  That said, the roller perches are better for longevity.

They might be onto something relocating the perches outward and utilizing the stock springs.  Saves the price of new springs and effectively increases the spring rate the old springs have because the suspension has less leverage to act on the spring, so it compresses less.  Haven't tried it myself.

MustangSteve wrote:

The Mustang Plus shocks are way too soft for my taste.  KYB Gas-A-Just are too stiff.  Regular KYB's are OK, and Bilsteins are great.  That from many years of trying different things on my car.  Your taste may vary!

I have a different opinion from my experiences.  I love the KYB gas adjust shocks however I run them with springs that are only slightly stiffer than stock.  If you are running stiffer springs I can see why the KYBs would make for a harsh ride but when running a softer spring they work better than anything I have found.   

 "A shock absorber (in reality, a shock "damper") is a mechanical or hydraulic device designed to absorb and damp shock impulses."

It is not there to add stiffness to the ride but rather control the spring. I am a firm believer (unless setting up a circle track car)  that the suspension needs to move fairly freely over imperfections in the road and through weight shifts when cornering.  IMHO by running a softer spring and a KYB gas adjust type shock you get the best of both worlds.  The suspension does its job and things move freely at slower speeds through rougher roads (city driving) but then the suspension stiffens up and rides like it is on rails at highway speeds.  In theory a highway should be a fantastic surface so minimal suspension movement is required.
 

MustangSteve wrote:

I agree, Daze, for normal driving, a better ride is achieved with a softer spring.  That is why I like the progressive motorsport springs so much.  The harshness of the old school 620 is gone.  Thanks to Tubo for telling me about them.
I used some Gas adjusts in the rear with a stock spring and they were too stiff for me.  Like I said, everyone will have a different opinion on what a smooth ride means to them.

However, things get way different when you have alot of horsepower and the car can jump around alot more.  I have found a little stiffer spring up front (*but not as stiff as the 620) helps you to keep the car on the road.

 
I read somewhere that the progressive springs are unpredictable during hard cornering because of the variable spring rate. It made sence when I read it but it was just someone's opinion. I have been running stuff that I purchased during the 80's and have been very happy, but then again I'm comparing it to the stock set up that was like driving a slinky.
TMC Motorsports 620 with KYB Gas adjust shocks, and Grab a track mid eyes in the back that were purchased in 2005ish. I just replaced the rear springs because the springs sagged on one side by 5/8" inch. I replaced them with some Scott Drake springs and Bilsteen shocks that I purchased from Shawn at Streat ot Track. I am excited to see what difference the new shocks make when I finally get it back on the road. On another note the Grab a Tracks have a lifetime warranty that I could have used, but the shipping back to them was rediculous so I decided to deal with Shawn at SOT. as I'm eventually going with his front coil over system..

boomyal wrote:

MustangSteve wrote:

...... Unfortunately all you can get other than roller perches right now are Taiwan reproductions.  .......

Why is that MS?
 

Even the roller perches  start out as imported parts... At least the ones I make do.

My 65 FB had KYB gas-a-just all the way around, with 600 psi springs in the front and 5 leaves in the rear and it was too stiff for my tastes.  I've since switched to hipo springs in the front and 4-1/2 leaves in the rear.  I installed Daze's roller perch kit and Opentracker's lower control arm kit and made my own own front adjustable struts (see my tips post). Still cogitating on the shocks.  Can't comment on the setup yet as the car isn't back on the street.

boomyal wrote:

BobN wrote:

Please consider moving the spring perches out 3/4 or 1". It was by far the best improvement to the way my car drove and handled. It will raise the front end back up after doing the shelby drop.

BobN

Ditto!  I did my perch relo at 3/4".  It came out perfect after the Shelby drop lowered my front end more than was advertised. It also gave the front end of my convertible a slightly more muscular feel.  BTW, I would only do this using roller perches.  IMHO, a relo of 3/4 to 1" would stress the rubber bushings, in stock perches, way too much.
 

                            Did you re drill the UCA holes for the perch's?
 

Thanks for everyone's input!  I appreciate the wealth of information!  I will just use the shelby drop for now and not cut the springs to see how the car sits and then I will look at other options.  I was going for the look that Mustang Steve did on his red (now blue) 65 Mustang coupe and I purchased the combination that he has listed on his ride height page.  It will mainly be a street driven fair weather car, no autocross or drags....  Thanks!  

Last edited by wemjr (5/19/2015 11:30 AM)

If you took a good look at how stock vulcanized spring perches work, I think, Daze, that you would include them in your essential list.  They may absorb more 'road' but they are destined to early failure.  This is all whether you relocate them or not.

So what is the benefit of moving the Spring perch out 3/4 of an inch?   How does it improve the handeling?

Experience tells me that you are best off with the lowest rate spring that will give the desired results. The spring basically controls the rate of motion of the sprung mass of the vehicle. And again, the least amount of shock damping to get the results you are after is a good thing. Bump shock rate determines the amount of "road feel" you are after as well as help with a crisp turn in. Rebound shock rate just keeps you from getting sea sick. You want as little rebound as you can stand because it is just trying to pull the tire off of the road which is a bad thing. Sway bars are to balance or neutralize from front to rear or determine if you see what you are about to hit through the windshield or rear view mirror.