Converting a 67 Mustang to a SN95/Fox Based SLA setup Info/Help

Hi guys I'm currently working on my 67 Mustang that was my first car and I took apart 10+ years ago and I'm finally getting around to working on it again and I'm looking for some guidance on my project/idea. Looking for the car to handle well through the  corners and mountains drives we have here and maybe auto cross in the future. Car is currently on a chassis jig I build to install the new front frame rails and I'm currently looking at coil over suspension options. After pricing out a whole brand new stock style coil over/steering front setup it came out to $5300 and if I wanted to go with a rack in an SLA SN95 setup it would be $6K + from Griggs/cortex racing. 

After doing some research I've been looking into creating my own SLA setup based on SN95/Fox SLA style suspension since that looks like where Griggs/Factory Five Racing/Cortex derived there parts from. They all use SN95 style racks with an option for SN95 spindles. I came across the autocross ranger (https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/autocross-ranger/126564/page1/) thread and this is what I'm most looking to do. My current plan to get started is to pick up a 94/95 Mustang spindle, an SN95 rack, and a SN95 lower control arm from the junkyard, and SPC universal adjustable upper arms for mockup pieces to start my design. If I can get the design setup to work I would switch the spindle to the factory five spindle which improves SN95 geometry and eliminates the need to use an adapter to attach the strut spindle to a ball joint, and the lower arm would be swapped out for the factory five which mimics the lower SN95 arm except its tubular with a coil over mount. Also looking to perhaps redo my front rails with 2x3 steel tube since the repo ones I have aren't the greatest.

While I'm fairly confident I can handle the fabrication portion the suspension geometry is where I need help. I'm a noob when it comes to this but have always been interested in it and with the lack of events to go to for the foreseeable future figured now is as a good time as any to learn. I'm looking for good resources that I can read/videos to watch that will help me understand where to put control arm mounting points, coil over length/selection, and anything else that might be beneficial to learn. Thanks for reading any help/replies is appreciated.

Firstly, this looks like a cool project!  Secondly, I don’t have any specific advice on setups, but the book How to Make Your Car Handle has been useful to me in the past to understand how different factors alter the way a car handles.  Might be a good place to start.

I'll be a dissenting voice and argue that you are going to spend a ridiculous amount of time, money and energy to fabricate a homebrew suspension system that will likely produce little or no gain over an updated OEM setup.  The old Mustang front ends are not sexy or fancy, but they have worked, and still work, under a wide variety of pretty awesome racecars.  Shelbys, early trans-am cars, sedan racing, et al have successfully run the OEM configuration with appropriate updates. There is a good selection of parts to support the cars.  Some modified geometry (Shelby drop) along with low friction, rigid bushing arms and struts combined with good spring and shocks will give you all the handling you would need in any street application or autocross.  Look at Opentrackerracing.com for some really quality parts for the old cars.  They have rack and pinion kits too if you just can't stand the OEM steering system.  You can then spend the savings on good brakes, chassis stiffening and updating the rear suspension which can't be ignored.

In reply to stukndapast :

I've done the research and don't disagree that the OEM setup is amazing and was planning to use the street or track coil over system and may still decide to go that route if this proves to be more trouble than its worth. My main reason for looking into this is since I'm starting from compete scratch essentially with just the front clip I can look into creating more space in the engine bay for the flexibility for doing a coyote swap down the road, have legitimate rack and pinion system, and the price and flexibility of parts that are available for fox/SN95 setups. I've looked into the steering setups for these cars as well with the Borgenson and rack and pinion and they both seem to either have a reduced turning radius in terms of the rack and the Borgenson is not as tight as a modern day rack. Before I spend to much money of this I'm just going to try a simple mock up with junkyard parts and modeling stuff in 3D with fusion 360. In the end if it doesn't prove to be viable I'll only be out a couple hundred and time. 

I'd look at fabbing in a RX8 front setup.  5-4.5 pattern,  great brakes, a-arms, unbolts from the rx8 complete.

Having done a couple Coyote swaps into early Mustangs I can say for sure the strut towers need to go and relocating or eliminating the brake booster is also on the list.  The brake booster won't clear the valve cover on a Coyote because it is so wide.  Also, if you end up using the Ford Racing controls pack, the layout of the harness will force you to mount the ECU in the front passenger side of the engine bay unless you modify the harness.  I cut and lengthened the harness in several areas so I could mount the ECU under the dash.  But, you have to be careful there too so it doesn't interfere with the windshield wipers.

Vorshlag is modifying an early Mustang right now for pure track duty with a pretty substantial budget and they decided not to go with a SLA setup.  Among other things, using struts on the front allowed for more tire clearance to fit 315's square.  It might be worth it to check out their blog or Facebook posts.

Detroit Speed makes a complete cast aluminum front subframe to bolt in that is a really nice piece but I also understand fabricating it yourself if that's what you really want.  I'm following and good luck!

That is pretty much what I did for my project. I used the rack from a Fox Body because I didnt need power and wanted Quick ratio.

In reply to Patientzero :

I've looked and priced out the DSE setup but it would probably around 8K to 9K into it just to get it in the car after brakes and everything is thrown on. Initial plan for the car is to get it driving and throw a SBF in it. Just want flexibility down the road for an engine swap and the space to work on the car in the engine bay since I plan on keeping the car. 

I've seen the vorshlag and will keep up with that build as well. I was originally going to go struts a few years back and had the AJE K member etc but then kept on reading reviews of all the issues with it and the poor welds and suspension geometry so I sold it. I've heard its improved though.

Below is the Griggs setup on a falcon though that I would be going for

In reply to MulletTruck :

That looks pretty cool. Any insight on how you set the geometry and mounting location for the front suspension you grafted in?

The Crown Vic aluminum removable front crossmember is all over the lowered truck crowd, and there are well established rack swaps that let you narrow it down to Mustang appropriate dimensions. Way easier than starting from scratch. 

I'm interested in the current definition of "Amazing" as applied to 60s small Ford front suspension.  

They are awful in almost every way imaginable.

Streetwiseguy said:

I'm interested in the current definition of "Amazing" as applied to 60s small Ford front suspension.  

They are awful in almost every way imaginable.

They actually perform really well when setup correctly and will keep with almost anything on the track with street or tracks coilover system for the front and rear which is track proven. 

http://www.streetortrack.com/Street-or-Track-Front-Coilover-System-pr-24491.html

In reply to sj9ers :

Yeah.  They are much better than a knee action 50 Dodge.  Compared to just about anything built in the last 4 decades, they suck.

I will grant that they were installed and raced in some fun cars.  That doesn't make them good.

In reply to sj9ers :

I leveled the mustang before I took off the crossmember. measured the angle in a few spots then duplicated it on the truck. i set the spondle in the same spot as the stock truck to keep the wheel centered in the wheel well.

The Cobra guys use this setup too, they just use an adapter to run a upper balljoint and upper arms.

Why not use a suspension based on the stock setup? Street or Track has great results with their coilover setup:

http://www.streetortrack.com/

It is FAR better to keep something based on the factory setup. As far as engine bay room goes....first off, seriously consider why you would want an engine swap to begin with...67+ shock towers can fit a big block ford engine....that is an engine capable of literally thousands of HP...you would gain nothing from say a Coyote engine...but if you insisted on a Coyote or Voodoo engine, you could STILL swap one in and retain full shock towers...you would just have to move them outward somewhat like the BOSS 429 cars:

I myself am swapping in a Ford 3.7L v6 from a 2012+ mustang....but its the same physical width as a 351w so no problem there....but the deciding factor in that swap was that I could drop 200lbs from the SBF weight while retaining a 300HP base....you can always make more power, but dropping engine weight is something else entirely. My vote is to retain the stock suspension setup...or rather something based off of it...it handles very well once the compliance is eliminated.

nimblemotorsports said:

I'd look at fabbing in a RX8 front setup.  5-4.5 pattern,  great brakes, a-arms, unbolts from the rx8 complete.

That seems like a brilliant idea. The wheel backspace/offset might be an issue if you want the old school deep dish look in the wheels.

Wicked93gs said:

first off, seriously consider why you would want an engine swap to begin with...67+ shock towers can fit a big block ford engine....that is an engine capable of literally thousands of HP...you would gain nothing from say a Coyote engine...

Umm... what?  

Linky here

Another vote for Street or Track here.  I have installed their system on my '69 Cougar.  Just spoke with Shaun (owner) today so I can vouch for his support too. 

mblommel said:

nimblemotorsports said:

I'd look at fabbing in a RX8 front setup.  5-4.5 pattern,  great brakes, a-arms, unbolts from the rx8 complete.

That seems like a brilliant idea. The wheel backspace/offset might be an issue if you want the old school deep dish look in the wheels.

That's a nice looking system but I cant see how you'd fit a SBF oil pan around that anti-sway bar and steering rack.    

wawazat said:

mblommel said:

nimblemotorsports said:

I'd look at fabbing in a RX8 front setup.  5-4.5 pattern,  great brakes, a-arms, unbolts from the rx8 complete.

That seems like a brilliant idea. The wheel backspace/offset might be an issue if you want the old school deep dish look in the wheels.

That's a nice looking system but I cant see how you'd fit a SBF oil pan around that anti-sway bar and steering rack.    

Who says you have to use SBF power? I'd like to see this suspension paired with a cheap F-150 Coyote and a TR-3650 transmission. 

In reply to Wicked93gs :

I'm not denying that street or track is an amazing setup. That was my first go to but after adding up the cost of what would be needed to run it since I'm starting from scratch its gonna be about 5500 to start after shipping I'm guessing plus whatever else I might need.

Currently I'm planning on re doing my frame rails in 2x3 steel since the repo ones I have seem to have some weird bow in them and I'm tired of trying to fix it and the repo shock tower motor mount/control arm mounts on mine are all out of whack as well. Everything is being done/modeled in Fusion 360 first so the components can be modeled  and geometry figured to see if its worth pursuing. I already have my frame jig that I mounted the car on built that's based on all of Fords 67 Mustang measuring points so getting suspension pickup points or measurements should not be an issue. My current plan is purchase an AJE K member which allows for the the mounting of a Fox/SN95 rack with Fox/SN95 spindles/arms along with struts to be mounted to a vintage stang and add upper arms to it and fabricate a coil over mount similar to the Griggs GR350 setup or Cortex racing which is almost the same design as Griggs and they both use fox/sn95 steering rack and spindles. 

AJE K member

Griggs Setup

In reply to sj9ers :

Sounds like a solid plan....as far as the aftermarket frame rails...I couldn't tell you, while much of the rest of my car was rusted to death, the frame rails were in good shape....I believe that is likely the same for most southern cars, you could probably find some from a parts car in good shape easily enough.Before I went through all the effort to re-design the wheel though(or in this case the suspension) I would start by settling on a final engine choice. In a previous '66 mustang of mine years ago I swapped in a 4.6L DOHC Cobra engine using a Mustang II front suspension...and while it was cool...the end result was certainly not worth it, it handled worse(worse than a rollerized stock setup anyway), steered worse, and didn't have any measurable benefit over a standard SBF....I could have gotten better performance with roller perches, boxed control arms and a very mild SBF build all without chopping up the car. The ONLY good thing about it was that I got rack and pinion steering, disc brakes and coilovers for a very reasonable price....but that rack an pinion steering was a let down because it didn't steer as well as the stock steering box, the brakes didn't stop any better than the factory drums(except in the rain)...the coilovers were fun to play with at least. The point is, you may well be disappointed to change the entire suspension just to fit an engine that doesn't gain you anything. I am a big fan of engine swaps, but these days I want them to fit in the factory engine bay. The only engine swap I would even consider chopping out the shock towers for these days would be a Voodoo 5.2L. If I were going to design a custom front suspension for a Mustang...I would not base it on a SN95 design...far better to go C5 or C6 Vette based. When they built the 2015 S550 chassis they started just re-designing the front suspension....then decided to add IRS as well because they improved the front suspension to the point that all of a sudden, the solid axle was holding it back. This is where the whole thing goes off the track....as individuals we are ill-equipped to design an entire suspension that works together and complements other aspects. The OEMs have huge budgets and a ton of test mules to find out what works best...all we have are educated guesses at best. I am pretty sure I am completely unable to out-engineer a factory engineer, which is why I am a bigger fan of making the factory design work better through improvements as opposed to re-designing it, but then, I am not an engineer either.

Alright guys manged to source a Maximum Motorsports K member for a great deal locally and will be using this under the car. Also have a set of MM control arms that will be used as well. Also have plans to use an S550 IRS like a couple of the Ranger guys here have been on this site in the rear by fabricating a rear cradle and frame rails for the car. Will be starting a build thread soon. 

Did you ever get anywhere with this project? I am looking at doing virtually the same thing with my 68 coupe and would like to compare some notes if you are willing.