stukndapast New Reader
Feb. 16, 2015 12:28 p.m.

After untold years and uncountable dollars dumped into cars that rarely need to turn...

and being subjected to seemingly endless abuse by the drag racing sanctions who gladly accept your hard earned cash but really wish you would go away, I got a hankering to satisfy my auto racing addiction in a different way. To that end I picked up a totally original 85.5 Mustang SVO with 76K on the clock thinking that 1) it would surely appreciate over the years since it is fairly rare, and B) it might be fun to try out other car competitions that involve more than my right foot. Mind you this was back in 2005 and, after attempting thought B) with an autocross or two on rock-hard tires and a ridiculous turbo lag compounded by a right foot which was well trained to be either on or off, I thought maybe I should stick with thought #1 after all. So the SVO gets parked in a quiet space in the shop where it slowly gathers dust and the tires continue to harden. An occasional drive keeps the thing from deteriorating excessively and maintains the hope of a reward for thought #1 over time.

Advance forward a number of years.... another uncountable bucket of cash and totally tired of the E36 M3 delivered in copious amounts by the soul-less straight-line sanctions I decide to stop feeding the beast and dust off the SVO. In its place goes the big yellow beast and its 429 cubic inches of true Detroit Iron where it can slowly harden its tires and collect the requisite dust. My wallet emits a deafening sigh of relief.

So, I think, surely someone who has spent the better part of his life messing with all things which involve internal combustion and wheels could learn to modulate his right foot enough to get a touchy car around an autocross course without it being a series of donuts and subjecting the course workers to excessive aerobic exercise and un-needed practice in resetting cones. Well, maybe. The obvious first thing to do is dispose of the vintage tires and get some whose hardness doesn't need the Rockwell scale to measure. Might as well get some new wheels while I'm at it since the OEMs, while made of aluminum, weigh like they are steel. So the first improvement is a set of Enkei RPF-1s with Hankook R-S3 in the OEM 225R50-16 size.

Major improvement! The driver still really sucks and seems unable to convert the digital right foot to analog, but at least the car doesn't exhibit drift-worthy oversteer anymore. But, of course, now that the rear is sticking better the front end pretty much ignores requests to turn with any amount of urgency and many, many cones continue to be subjected to levels of torture that would make Dick Cheney wince. Along the way the leaking master cylinder gets fixed along with fresh high temp brake fluid and some new pads and flex lines. If I learned anything from drag racing it is that the stopping part is at least as important as the starting part.

So on it goes and the driver keeps autocrossing and seems to improve at a glacial pace, but enough to get cocky. What the heck, surely I can do better than second gear romps around a parking lot! After all I am used to 120+ MPH runs down the dragstrip. I feel a need for speed. What better way than a PDX session at an easy road course, sort of like a spirited romp through the backroads on a Sunday morning. Mind you now, that other than the wheels, tires and brakes, this thing is totally bone stock, right down to the 30 year old hoses and paper air cleaner. Other than oil changes, it doesn't look like the drivetrain has ever been touched.

Undeterred, off I go on the 2 1/2 hour trip to, wait for it ... Hello Road Atlanta! HOLY CRAP! Now, you would think that someone who has been racing cars since the early '70s and broken enough stuff to fill a junkyard would have better sense than to partake in such an excursion. But no, he drives the car to the track having no backup plan for getting home if the engine scatters its guts or an unplanned encounter with the wide array of available walls occurs. Fortunately, for whatever reason, advantageous planetary alignment perhaps, the trip goes off without a hitch. Well, other than needing a clean set of drawers after the repeated launching into space on the way under the bridge and into turn 12, and a few signs of overheating near the end of the session, this intrepid traveler and trusty steed made it there and back intact. How unfortunate, since there is nothing worse than a successful, adrenaline stoking first outing in a new endeavor to lead one into a mine field.

What I know about making a car go around a corner can be easily summed up with one word, nothing. I know how to make a 3600 lb. car with 600 ft-lb of torque hook on 9" slicks well enough to pull 3 foot wheelstands, but getting said car to turn onto the return road at a crawl doesn't take a lot of skill. Research ensues. There are serious advantages to messing with a 30 year old car since the road is littered with carcasses of previous souls who had made similar attempts. The survivors of such attempts have either learned their lesson and moved on to more modern and capable platforms, or have started companies that supply an astonishing array of paraphernalia to people who cannot or will not abandon the attempt to make a fundamentally flawed design perform in a manner that is the least bit comparable to more modern designs. The owners of such businesses are called "entrepreneurs" while their customers are called "delusional". Count me among the latter. The former can thank me later.

So the first order of business is to revisit item #1 from way back at the beginning. Do I want to start messing around with a valuable classic collector car and subject myself to the scorn of the concours restoration crowd who will lop $10K off a car's value because the crossmember bolts are cadmium plated instead of black oxide and the shade of the red paint slash on the rear axle housing isn't quite right? Do I risk missing out on the joy of seeing my desirable classic get the high dollar hammer as it crosses the Barrett-Jackson stage because I stupidly welded a set of subframe connectors onto otherwise pristine OEM stampings? Further research is in order. Research complete. Yeah, it is a uniquely equipped and limited production vehicle with only 9844 examples built over its three year run. My particular version, a half-year introduction in 1985 is the rarest of the group with only 439 built. But all said and done, it is a FOX BODY MUSTANG and there is virtually no one on the planet that gives an E36 M3 about it other than a small group of aficionados, some of whom are vociferously militant when it comes to preservation of these cars. As a group these guys seem to create an endless demand for the special parts that came only on the SVO leading to the unfortunate situation where it is more profitable for the average joe who stumbles upon a SVO to part it out than to sell it complete. Indeed, over the course of a year or so of watching the market I see several examples of unmolested, minimally rusted, drivable and truly restorable cars, some in better shape than mine, being dismantled and the choice pieces sold to the highest bidder. Prices for complete cars are about what you would expect to pay for any Mustang of the same era, mileage and condition, which isn’t much. Also, it seems unreasonable to think that a Fox Mustang of any ilk would someday rank among the collectable classics that demand a high price… I’m thinking Boss 302/429 or early Shelby stuff here. Time to fire up the welder!

First thing is to install said subframe connectors as the Fox unibody is notoriously flexible. You’re welcome, Steeda.

Somewhere along the line I read that the FoMoCo limited slip diff is limited in other ways too, and the state of the art is a Torsen differential. Unfortunately the SVO came with the 7.5” rear with a 3.73 ratio. The Torsen is only available for the 8.8” rear. Happily the rear housing from later model Mustang GTs that came with the 8.8 will fit right in and the special axles used to accommodate the rear disk brakes on the SVO work too. The other good thing is that these rears are ridiculously common and can be had for next to nothing. So a nice unit from a ’89 GT is found and a new set of Ford Racing 3.73 gears are fitted to a Torsen diff, buttoned up with a pretty cover and out comes the 7.5 which I will trip over repeatedly to this very day.

Well, going through all the effort to replace the rear end opens a nearly bottomless can of worms, of course. Since the control arms come out it makes no sense to put them back in without new poly bushings. I began this operation with the intention of keeping the car compliant with SCCA ESP autocross rules for no apparent reason since I don't really compete in autocross, I just go to have fun. However, it is nice to have a basic set of rules to go by. At the time, ESP rules required keeping the OEM lower control arms. Naturally, since I went to all the trouble of putting poly bushings in the lower arms the rule has changed to allow aftermarket LCAs, and gave an uncomfortable reminder that race sanctioning bodies are pretty much the same whether you go straight or turn. The OEMs remain for now.

The Fox rear suspension has been call many things, most of which cannot be repeated in mixed company, but it is pretty much the best suspension system that a bunch of accountants could design, naturally resulting in an engineering E36 M3 pile. The intentional binding of the unequal length and weird angle four link has to be fixed. Implementing a better way of controlling lateral axle location is the first order of business. A panhard rod or watts link are legal for ESP but a torque arm is not. A panhard rod is cheaper and easier to install, but the Fox can't have a really long arm without interference with all sorts of items. The Fays2 watts link is a tidy package that is easy to install and provides the ability to adjust the rear roll center by moving the propeller axle. It also changes the role of the upper arms from lateral location duty to mainly setting the pinion angle. That means that the bind-o-matic UCA bushings can be replaced with spherical bearings.

Naturally something had to be done about the springage too so a set of H&R Race springs were tossed into the mix.

Enough for now... some front end work is next.

oldeskewltoy SuperDork
Feb. 16, 2015 12:54 p.m.

Wow......... nice write up... great handle of the GRM perspective too

I once owned a Fox bodied Capri... 1980 ordered to the best spec of that time... turbo, TRX, with Recaro. Later dumped the stock springs and dampers for stuff I bough through Racer Walsh... including a turbo wastegate delay kit... could turn up the boost from inside the car

wheelsmithy HalfDork
Feb. 16, 2015 1:13 p.m.

Incredibly interesting, and inline with my interests. Question; dual exhausts on a SVO, or are these "stock footage" pics? I can't help but wonder the same things you did. For example, will anyone lament the days of $2000 SVOs once they are Barrett/Jackson material? Regardless, thanks, and I love the things that our are doing.

tuna55 UltimaDork
Feb. 16, 2015 1:18 p.m.

I had the exact same issue at Lemons with the digital throttle pedal. I figured heck, this thing only has 85hp, I ought to be able to just whack the throttle. Nope.

It's all fun. Keep this thread up.

The_Jed UberDork
Feb. 16, 2015 1:24 p.m.

Sweet car and I like where this is headed!

Is that a shed snake skin on the driver's side of the rear axle in the last pic?

stukndapast New Reader
Feb. 16, 2015 2:17 p.m.
wheelsmithy wrote: Incredibly interesting, and inline with my interests. Question; dual exhausts on a SVO, or are these "stock footage" pics? I can't help but wonder the same things you did. For example, will anyone lament the days of $2000 SVOs once they are Barrett/Jackson material? Regardless, thanks, and I love the things that our are doing.

The dual exhaust first appeared on the SVO on the 85.5 half-year model and continued through the 1986 production. Earlier cars had a single exhaust.

I am doing my best to keep everything I take off the car and avoid any major hacking that would be really hard to undo.. although we will have to see how that plan works out!

stukndapast New Reader
Feb. 16, 2015 2:23 p.m.
The_Jed wrote: Sweet car and I like where this is headed! Is that a shed snake skin on the driver's side of the rear axle in the last pic?

Does look like a snake skin, doesn't it!!?? It is the loose end of one of those friction-lock tie-down straps. At that point I was using two straps to hold the axle in place until I got the shocks installed. If I looked around the shop enough I probably could find a few snake skins. I live in the boonies and there are plenty of snakes around!

paddylopez New Reader
Feb. 16, 2015 2:23 p.m.

This answers one of those questions I've had about the Fox-link suspension. I've heard that even urethane UCA bushings were a no-no because of the lack of compliance (and thus snap oversteer!). I suppose that the Fays2 Watts Link handles the side-to-side locating of the axle, right? So the LCA's now handle controlling the pinion angle and thus, no worries about binding. Am I on the right track?

RexSeven UberDork
Feb. 16, 2015 3:00 p.m.
paddylopez wrote: I suppose that the Fays2 Watts Link handles the side-to-side locating of the axle, right?

Watt's links control the side-to-side motion of the axle in a more linear fashion than Panhard bars, which move in a slight arc. On the other hand, they are heavier and more complicated, but in some applications the handling improvements are worth the tradeoff. I have a Fays2 on my S197 Mustang and it works well along with the Koni shocks and Steeda lowering springs I have on it.

paddylopez New Reader
Feb. 16, 2015 3:06 p.m.

In reply to RexSeven:

SWMBO and I are looking at an SN95 to play with, so these kinds of things are very useful to know!

stukndapast New Reader
Feb. 16, 2015 3:44 p.m.

The front end got a similar treatment as the rear in that poly bushings were added to the control arms and the H&R springs were installed. The SVO came from the factory with Koni adjustable struts but I found that one of the OEMs was blown. They are rebuildable but you can get new ones for about the same price so that was the route I took.

The topside of the struts get the caster/camber plate treatment.

Back on the ground the stance is greatly improved from its previous monster truck ride height.

pinchvalve MegaDork
Feb. 16, 2015 4:08 p.m.

Snicker, my Fiesta ST has more HP and torque and larger tires than a stock SVO. Great car, can't wait to see what else is in store for it!

Junkyard_Dog SuperDork
Feb. 16, 2015 4:21 p.m.

The value thing will hit hard when you least expect it. I'm building a Chevette for the challenge and instead of finding clean ones for under $1000 I'm finding rot boxes for double that-and the Chevette has even less of a following than the SVO. Except for the welded in braces keeping the old parts handy and the new mods reversible is a good idea. And if those braces hurt the value in 20 years, that's what grinders are for.

stukndapast New Reader
Feb. 16, 2015 4:31 p.m.

In reply to pinchvalve: Yeah, that ad was for the original 1984 SVO which was detuned compared to later years. The 85.5 was spec'ed at 205HP and 248 lb-ft. They cranked up the boost and put a different intake manifold on it. My plans are to do some engine work but not go crazy. I'd like to get 250 to 275 RWHP at some point and from what I have read that is not terribly hard to do with the 2.3L four. Engine work has to wait for the rest of the car to get it's massage.

stukndapast New Reader
Feb. 19, 2015 3:29 p.m.

To add some context to this build, my goal for this thing is to have a competent car for track days and autox, but my main goal is to run in SVRA events. SVRA has informed me that I would be in Group 6/MP class. To that end, I am trying to only do modifications that will keep me within the rules for autox ESP and SVRA Group 6. SVRA has a lot of safety rules that exceed autox while autox is a lot more permissive than SVRA in some areas. SVRA requires a FT-3 fuel cell and at least a roll bar along with a 5 or 6 point restraint, a SFI 38.1 Head and Neck restraint and a minimum 2 lb fire extinguisher. ESP allows but doesn't require any of that. Alternately, ESP allows larger diameter and width wheels, R-comps and other-than-stock brake setups, none of which are allowed by SVRA. Both require an un-gutted interior but allow a racing drivers seat. So I am walking a fine line which I will likely stray from on one side or the other. But, since I am in this for enjoyment and not to be out for blood, I think I can make it work. SVRA is going to be less flexible, especially on the safety side. I can just claim a more permissive class for SCCA if necessary.

So, to that end, I had to figure out a way to get a FT-3 fuel cell without taking out a second mortgage. I decided to go with a 12 gallon ATL "Well Cell". You can actually buy a FT-3 cell that fits in the place of the original bizarrely shaped gas tank, but it is stupid expensive. I will also need to put in some sort if roll structure so the interior needed to come out.

The fuel cell was mounted into the spare tire well after taking out the spare tire hold down strap. Aluminum straps were fabricated to mount the cell and the plumbing was done with 6AN braided line. An external Walbro 255LPH pump was installed.

In keeping with the minimal hack-up of the car, the braided lines connect to the OEM fuel feed and return lines. The feed goes to an OEM style filter in the original location while the return connects to the braided line with a Russell AN to SAE adapter. I even used an original opening in the deck for the feed line. The pump is powered by the original wiring harness.

The cell and pump will have to be covered with a fabricated enclosure to isolate them from the driver compartment. I'm not sure whether I will tackle that myself or let a fabricator do it. If I take it to a fabricator for a custom roll structure they could probably do the enclosure too. I'm undecided about the roll bar/cage. Maybe the community has some ideas about the right approach.

I don't need a cage, although I am not opposed to one. The minimum is a four point bar with a main hoop and rear supports. I am considering several options, both bolt-in and welded, custom and off-the-shelf offerings are possible.

Autopower has both a bolt-in and "u-weld" four point bar with the required diagonal and cross brace for the belts which are said to be SCCA and NASA compliant. Those look pretty good to me. I think I would lean toward the bolt-in for simplicity of installation and ease of removal if necessary down the road. On the other hand, my drag car had a bolt-in roll bar and I didn't like how it mounted and the backplates were a pain. It seemed like a hack. My welding skills are not fabulous, but they aren't awful either, so I could probably manage the "u-weld" version of the four point. I am leaving the rear seat out (this is OK for ESP autox since the SVO is on the same line as the '93 Cobra R which had the rear seat deleted) so I would not have to have the rear support bars terminate at the wheel well, which looks like what the pre-fabbed bars do. Kirk Racing also has pre-fabbed bars and cages and they are not too far from me. They could also do a custom at any level of fancy I want.

Alternately I can take the car to one of several local shops who do nice work. That choice would surely be weld-in and if I were to spring for a custom job I would have a cage done and not just a bar. I don't know. Any ideas?

dropstep Reader
Feb. 19, 2015 5:00 p.m.

i cant lie, I was a little sad reading this because im a foxbody fan but I don't own the car and I find any use better then letting them sit. ive also parted out a 2 turbo coupes and a merkur so I like the idea I would just try really hard not too stuff an original into a wall and please don't 5.0 swap it!

mbruneaux New Reader
Feb. 19, 2015 5:10 p.m.

I've always been a GM guy but always really loved these SVOs. Nice save.

Woody MegaDork
Feb. 19, 2015 5:52 p.m.

I love this. Good job!

pres589 UltraDork
Feb. 19, 2015 6:02 p.m.

This is another case of RFP-1's looking excellent on a car. They look good on everything!

Cool project, and good writing, thanks for starting this thread.

Vigo PowerDork
Feb. 19, 2015 6:29 p.m.



I like the build.

BlueInGreen44 Reader
Feb. 19, 2015 6:38 p.m.

I like this fox Mustang thread. I first learned about the SVO Mustang when I was about 13 and a guy I knew was putting a built V8 in one. I remember being confused and wondering why he didn't just put the V8 in a regular Mustang and leave the cool "Euro" Mustang the way it was.

catapultkid New Reader
Feb. 19, 2015 9:31 p.m.

2.3 turbo ftw. Looks fantastic! Soft spot for these and turbo coupes

JacktheRiffer Reader
Feb. 19, 2015 11:02 p.m.

This is an awesome thread! Fun to read.

Sky_Render Dork
Feb. 20, 2015 10:13 a.m.

I love the writeup!

fidelity101 SuperDork
Feb. 20, 2015 11:56 a.m.

get a license plate that says SVOYEAH or SVOYAAA

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