yldouright

If you guys are interested in a daily driver that can keep up with anything in its class on a road coarse, then the idea of a Fox body with some chassis work and an LS heartbeat might have crossed your mind. It has mine, many times but I've never gathered the nerve to try it until now. This thread will discuss the strategies that will lead us to a great handling, 8lbs/whp car that won't annoy your neighbors. I will be looking for a $1,000, 1979-1989 classic Fox hatchback to start this project and hope to get my result with <$10,000 sunk. With your guidance, it just might happen. Here's how I would like this to work:

All the part selection choices will be presented in this first post and discussed by anyone following along. In this way, the end result will be evident in one orderly place in the form of a plan and how we got there will be in the member posts. Okay, the first step is the platform selection. I know the Fox notch is favored over the hatch for most mod projects but the notch has 0.02 worse Cx drag numbers even with air treatments and the hatch is more convenient as a daily so the hatch it is.

1. Which hatch? Here's what's available to me:
a) 1989 GT Mustang, 136K on the clock, blown motor with a worn out Limited diff, worn tires, shocks and bushings bad paint and few dings. Not much rust, decent interior but repairs required, wheels good and manual tranny. $1,100
b) 1984 LX Lima Mustang, 80K on the clock, well maintained, garage kept, clean with good interior, auto tranny. $1,500
c) 1986 SVO Mustang, 114K on the clock, good interior, undercoated with no visible rust, blown turbo, bad tires, passenger front wheel damage (slight deformation) and broken tie rod same location, Body has some dings but paint looks okay. Found under a under a canopy and looks like it sat for years, manual. $1500
d) 1987 GT Mustang, 96K on the clock, fire damage, no motor, broken driver side window, bad interior, some rust but no dings, torque boxes look okay, auto tranny. $600

So do I jump on one of the above or wait for something better? Only choice d) fits my budget but the others are close and I can sell parts to offset the cost or possibly integrate them into the build in some cases. What would guys start with and why?

79LS1FOX

iTrader: (11)

why do a hatch>

RidetechJosh

^ It sounds like that's just what he prefers. I'd pick whichever one is the cleanest out of the ones you listed. Finding one that is in good shape, cheap, isn't easy these days.

yldouright

Welcome to my thread. Yeah, it's mostly a personal preference but I'm also swayed by the lower Cx of the hatch.

@RidetechJosh
The Lima (choice b) is the cleanest by far but the stock manual tranny is too weak to handle the >400ft-lbs of torque planned in this project. I'm tempted to pull the trigger on the SVO but the front end damage scares me there might be other unpleasant surprises. I'm thinking the T5WC in the SVO can handle the torque but it has a piddly 7.5 rear axle that may not work properly with a T2 torsen diff. Has anyone here mated the 7.5" Ford rear to a torsen pumpkin and if so, which one?

modernbeat

While this doesn't really apply to the hatch vs notch bodies, as they both have the same frontal area, you are falling into the trap that many get caught in when they think about aero.

Don't be swayed by the Cx of a car. Look at TOTAL DRAG, not the coefficient. Large cars with greater frontal area have an easier time getting their Cd or Cx down, despite having higher total drag numbers.

yldouright

@modernbeat
I got the number difference from wiki page that had bunch of cars listed. It may not have been a total drag number but I think it may have been. How could you get "total drag" numbers without putting into a wind tunnel with air dams installed and the car sitting at the height you intend to run it? That said, doesn't the hatch look more aero?

Bowtiedford

iTrader: (9)

Yeah but a coupe looks so much cooler. Just add more nitrous, or boost to make up your drag coefficient.

yldouright

@BowtieFord
I'm not a straight line kind of guy Seriously, I'm looking for a car that won't be a public nuisance but still go fast around a track and Cx can matter there, nitrous? not so much. Anybody here know if the Chevy T2-R works with 28 spline axles?

Bowtiedford

iTrader: (9)

I'm not a straight line of guy either lol, like a car that can handle well also. My dad raced for Porches years ago, I mean year lol they where always in the wind tunnel, now that was cool to watch. I do remember one of the engineers saying unless your well above over 100 mph for a long straightaway aerodynamics not that big of a deal in some of the SCCA cars. But he said it does look good with all those wings, spoilers etc lol . God luck and have fun. A 7.5 rear will not hold nor would I trust it. A 8.8 many guys have run in the 9's even on stock axles. Is it safe, no. I would not trust stock c clip axles on cornering as the load from side to side I imagine would be to great. C clip axles fall out and can cause a lot of damage as when they are retained with like 9" ends or a c clip eliminator kit if they break they still stay in place.

gnx7

iTrader: (28)

By the time you upgrade the suspension on the Fox body to actually handle well, source an LS engine, install a T56, do the gearing out back, add big brakes..... maybe you should just look into buying a 2nd gen RX-7 that has far superior suspension, aerodynamics, also lightweight, 50/50 weight distribution, IRS out back, etc. There are others for sale with LS engines on the norotors.com facebook page.

$11K obo
http://www.norotors.com/index.php?topic=26445.0

yldouright

@gnx7
Thanks for the link. Your points are well taken but a fox with an LS can reach close to a 51/49 weight distro, have equal GVWR and still carry four passengers comfortably

@BowtieFord
That's a tip I'll take, the 'C' clips make me nervous too. As an aside, I've heard you can run the 8.8" axles in the 7.5" housing. If this is so, is it because they're the same axles or because there's enough space in the 7.5" housing? While we're on the topic of axles is there any difference between the axle end patterns of different makers if they have the same number of splines?

Stampede4ever

They share the same axles.

Stampede.

Michael Yount

iTrader: (1)

Go 8.8" in it and be done with it; forget the 7.5". You'll have a tough time getting to 51/49 -- but that doesn't mean it can't be made to handle reasonably well. Be sure you go aluminum block or you'll be ADDING weight compared to the 5.0L. The difference in drag with the hatch is negligible - don't worry about it; proper deck lid spoiler will get most of it back. LX notch about 130 lbs. lighter than a GT Hatch. Go notch.

My "4-eyed notch" was 5.0L powered for 19 years before the aluminum LS went in.



Attachment 712560

G Atsma

FIIIIIIIINE- lookin' Q-ship you got there, Michael! (Remember Ferd Burfel (Dick Martin) of Rowan and Martin?)

yldouright

@G Atsma
+1. I would have said that if you hadn't said it first. I don't get the reference, what does Burbank/Laugh-In have to do with that car?

@Michael Yount
Noted, even the aluminum blocks come in at 478lbs. complete. Beautiful work! Who needs an M5 when you have that ride The chin spoiler up front makes the look of your car, how do I get one? All the notches I've seen come with a 7.5" ring, why add the install headache and ~40lbs. of an 8.8"? I was planning on an LC9 and a snail for my build, did you use the stock mount or get an aftermarket "K-member" to seat it? I have so many additional questions but I don't want to overwhelm you in one post.

@Stampede4ever
Thanks. Just to clarify, are you saying ALL 28 splines will fit ANY manufacturer ring gear differential, including torsens or that Ford 7.5" and 8.8" house the same axles? Has anyone done a compatilbilty list of axles and rears? I think I want a T2-R diff on my build but only if it isn't too much trouble.

Michael Yount

iTrader: (1)

I weighed the LS3 and the 5.0L that came out of mine in comparable trim. No flywheel; balancer on; tubular shorties on the 5.0L and the F-body crate cast iron manifolds on the LS3; fuel ignition and injection systems; no accessories. LS3 - 393 lbs; 5.0L efi/HO - 411 lbs. The issue isn't how much the aluminum engine weighs - it's how much MORE a cast iron block LS weighs than the thin-wall cast 5.0L. If you're serious about getting close to 51/49 - you need the reduction the aluminum block is going to afford. Mine's 53/47 off of corner scales and the fox bodies are a bit more nose heavy than the 200 Volvos. Any cast iron block LS variant is going to come in a good 75 lbs. more than the aluminum block. You're also going to want to move the battery to the trunk AND use one of the fox body aftermarket cross members that allows setting the block further back.

Why "add the install headache" of the 8.8"? Because you'll break the 7.5". Hell, I tore one up in a 2.9L V6 Bronco II towing a 3500 lb. trailer/car combo. All HO SEFI V8 fox bodies came with 8.8's - the 2.3L 4 cylinders came with the 7.5" rears. I run an 8.8 in the Volvo because the stock Dana 30-based rears in these aren't up to the LS3 task (Heavier duty 1031 rear - 7.75" ring gear). This car has been V8 powered since '96 -- don't even think about the 7.5" rearend.

Stock Volvo cross member notched so I could get the engine/tranny in/out by myself. The pan would clear once it's in -- but you need the room for installation/removal of the engine/tranny when mated. I fabbed the x-member changes and the motor/tranny mounts. If you have more questions, fire away. Build thread here -- https://ls1tech.com/forums/conversio...lvo-242-a.html . I realize you're doing a Stang - but since mine was Stang powered for 19 years, there may be some overlap.

Trust me - you want the 8.8" rearend. Snag one out of an Explorer - you'll have to modify tube/axle length - but you can have the rear disc brakes and while doing that you can use the 9" tube ends/bearing retainer to get rid of the C-clips. And most come with 3.73 trak lok set ups.

yldouright

@Michael Yount
Noted, aluminum block it will be. About the 4cyl. Fords, I heard the SVO came with both 7.5" and 8.8" rears but I didn't see the 8.8" offered as an option in any year, can you clear this up? I've read more than a few members claim their ~250whp V8s break their T5s withut a hiccup from their 7.5" rears. They seem to think its up to the task, were you on even ground when you ground up yours in the Bronco? I've read stress on the pinion angle is more to blame on 7.5" faliures than any inherent weakness. I don't know either way, I'm just taking in the information at this point. Are you running the stock Volvo axle shafts (28spline?) with the Ford 8.8"? I'm glad to hear that your T5Z is holding up for you, there's lots of warnings on the net about that being a 'glass box' with the power you're making. Which clutch are you using with it? If you put the engine and transmission in as one unit by yourself, how did you manage that? I've read that the stock Fox cross member seats the LS without a modded oil pan but I'd like as much corroboration as I can find before I fully jump into this project. How deep and at what point in its length did you notch the member in percentage terms? I hope I'm not abusing your offer to "ask away"

rtagg

iTrader: (2)

The SVOs all had 7.5's the heavier '87-'88 Thunderbird turbocoupes had 8.8's. My '86 SVO 7.5 at 40K miles started making a lot of noise after only 2 track days at Watkins Glen. I switched to a T-bird 8.8 and never had any more problems. The T5Z is a good stout trans, but the stock T5 really isn't up to the task at the 350-400HP range. I broke a couple of them on road courses before going with a T56. Hope this helps.

Michael Yount

iTrader: (1)

yldouright - we're all telling you the same thing - forget the 7.5". So I'm letting that go now.

The fox body Mustang 8.8's had 28 spline axles. The Explorer 8.8's have 31 spline axles - that's what you want if you wanna avoid twisting the 28's with a lot of traction/launches. I run Moser 31 spline axles in my 8.8 with a Truetrac LSD.

The stock Ford V8 T5 was rated for 300 lb-ft; the aftermarket T5z for 330 lb-ft. The T45 for 400 lb-ft. Keep in mind these ratings were with a warranty in mind; so the trannies may stand up to a bit more -- but not with a warranty that I'm sure Tremec stood behind Ford with. I'm of the belief that the T5 has the reputation it does largely because -- 1) people buy them used -- in most cases already worn out or improperly rebuilt; 2) they put them in something with more torque than they were designed for; 3) they break; 4) people conclude the T5 is shitty. The T5 will do what it was designed to do. If you're running a street car with 300-400 lb-ft and not abusing it -- it'll likely lost a good long time. If you're sidestepping the clutch at 5500 rpm with drag radials or slicks on a regular basis; or speed shifting it; or road racing it AND asking it to deal 400 lb-ft of torque - yeah, you're probably going to have trouble even with a new one. It's not complex - determine your torque output, how much traction you're going to have and how you're going to use/abuse the car - then pick your tranny accordingly. T5 weighs about 75 lbs; TKO about 105; T56 about 130. Much of the difference is in rotating weight which creates parasitic loss. Couple of acquaintances - one Stang, one Camaro - both did before/after dynos with only a swap from T5 to T56. Both lost about 20 rwhp with 350-ish rwhp combos. If you need the T56 to manage your output/use, then you need it. But if you don't, you pay a price for using it. Same with rearends - the Ford 9" is virtually indestructible. But it weighs more than an 8.8" and because of the design having more pinion teeth engaged with the ring gear - it takes more HP to turn it. If you need it - you need it. But if you don't - it adds unsprung weight and eats up HP.

I can't help you with your fitment questions about LS into Stang - but there are TONS of threads here about that swap. It's not rocket science. Most buy a different K member that's set up to accept the LS. Holley makes a first rate kit. You'll be fabbing yourself if you wanna go with the stock Ford k member.

Not sure I understand -- "If you put the engine and transmission in as one unit by yourself, how did you manage that?" Bolt tranny to bell to engine. Pick it up with cherry picker. Lift it over the bumper. Use angle changer to angle it down. Lower into place while slowly moving it backwards and bringing the angle back to something approaching level. Removal is the reverse. Easier with another set of eyes/hands? Yes. Do-able by yourself? I had it in/out by myself 11 times during mock up. You've got to have a device that allows you to change the engine angle while raising/lowering.

Oh - Quicktime 6037 steel bell - mates T5/top loader/TKO to LS; McCleod aluminum flywheel, PP and clutch disc.

yldouright

@Michael Yount
Some of my questions were answered in the thread you linked but I was so enthused I asked them before looking all the way through it. Sorry about that. It looks like you just notched the member to get the engine in but bolted your fabbed section in afterward to beef it back up, is that correct? I've never pulled an engine and tranny so had a hard time imagining how it could be done without your explanation. I believed you could mate either side to the other from underneath the car. How do you keep the oil from getting all over your floor when you have it angling in and out so many times? Did you fashion a plug with plywood or use some other method?

@rtagg
That's what I thought too but others insisted the 85-86 SVO's used the Lincoln Mark VII rear ends which were 8.8 with longer axle shafts. I'm not arguing, just trying to reconcile the disparaties. I'll try to find the link I was shown and pop it in here.