customblackbird

iTrader: (15)

ive talked about this before but im really seriously thinking about doing the swap over my already worn posi 9bolt. lighter than stronger than the 12bolt and cheap the ford 8.8 is a good choice

what i need to know is the lengths of the stock 9bolt rear end housing and the lengths of the ford 8.8

as far as the swap. i would swap everything over to the ford 8.8. brakes, LCA/panhard rod/spring mounts. and i would get a tq arm mount from currie and have it welded to the cast iron section. so really all i need is the housing/internals. but i need the the lengths for this. if i found one from an explorer and it had rear disk brakes i would keep them on. but i dont kno the housing lengths of the 2 rear ends.

ford 8.8s are pretty cheap my friend just sold his for 75$ with a posi about 6months ago!! D@MN!! lol and are stronger than 12bolts if i upgrade the axles to 31 or 33 splines.

big gear head

Welding steel to cast iron is very tricky. You better get someone who is very good to do the welding. It MUST be done with nickel rods, which are hard to run. Preheating is also very important, along with metal prep.

The 9 bolt is 61 1/2 inches wide without the brake rotors, so it's probably 62 inches with them.

Shagwell

Depending on what the 8.8 you use came out of will determine it's width. Different model vehicles have different width rears. None will have a bolt pattern to fit GM wheels. Whether or not it is stronger than a 12-bolt is still a lengthy arguement. Stock for stock, probably a little, aftermarket part for part, they're about the same, except no one makes a soft 9310("pro") gear for an 8.8 . - The regular 9" type bracket will not work well for attempting this.

As near as I can tell the 8.8 housing are cast steal. The two that I have welded to were definitely not regular gray cast-iron. I had no issues MIG welding to them, but I did warm the metal and drastically slowed the cooling process. - I bent two pipes to form a "bridge" above and below the housing center section and welded to both the axles tubes and the housing. Since both the rears I've used had the vibration damper mount(near the pinion), I ran two pipes(one either side the housing, two per "bridge" pipe) down to the damper mount ears and welded on a tab to bolt through the holes. I used 1-1/4 DOM for the bridge pipes and 3/4 DOM for the brace legs. - Basically the housing looks like it is contained in a cage. I put tabs on my bridge pipes and built the torque arm from there.

The only pics I have right now are on my phone and I have no way to put them up(I purposely have all the extra service crap shut-off). If I get a chance to get some with my dig camera I'll post them up.

customblackbird

iTrader: (15)

ive got a list of ford 8.8 rears and there widths. the only one thats 61" is a 71-73 mustang but im not looking for one of those lol. prob go with a 97-later explorer rear, since they have 31 spline axles and disk brakes. the 86-93 stangs have a width of 59 11/44... so they are not far off. and i might have to run small spacers for the rear.

shagwell... i would be really appreciate the pics. i would love to see how u did it. i already installed the jegster tq arm. so im not totally sure how i iu would attach a tq arm mount to the rear, ive heard of ppl just mig welding the currie tq arm bracket to the iron section. the jegster tq arm is a stock replacement so the bracket would have to be in the the stock location. but your pics would help immensly.

now about the bolt pattern. most of the early ones are 4lug and thats cr@p. but later in 95 they switched to 5lug. are the 5 lug rears the same bolt pattern as ours? 5x4.75"

heres the specs on a 97 explorer 8.8
31 spline axles= 6500lb breakage
axle DIA=1.32"
total length= 59 3/4"
axel tube DIA= 3.25"
disk brakes, track lock limited slip

heres a carcraft article on the ford 8.8 swap and how its strength compared to a 12bolt. remember the one i want is a 97 with 31 spline axels so its 10.7% stronger than the 12bolt.

AlkyIROC

12 bolts have 30 spline axles and can be easily upgraded to 33. Axle and ring gear size doesn't account for strength. There are so many other factors. Pinion diameter. Pinion placement. Bearing arrangement and sizes etc. A car 12 bolt is stronger than a truck 12 bolt although they're both GM 12 bolts.

Ford lug pattern is 5 x 4-1/2 although it's possible the very newer ones are metric but I doubt it. The explorer diff also uses small axle bearings which are not as strong as the older "big bearing" diffs.

If you're swapping in a junkyard diff because you're making enough power to need one, trying to fabricate a way to mount the torque arm isn't the way to go. If you were doing a leaf spring setup or a ladder bar, 4-link with coilover shocks then any junkyard diff that would fit will do. Under hard acceleration, the diff wants to rotate upward. That's a lot of stress on a cast welded mount for the torque arm. If it breaks, your car is toast. Since the cast needs to be preheated and preheated a lot before welding, how much do you think the case is going to distort after all that heating and welding. Will the pinion or carrier bearings still be in line?

If you're producing enough power that you need a stronger diff and want to use a torque arm, buy a proper bolt in 9", 12 bolt or Dana 60.

How do you figure factory 31 spline axles have a 6500 pound torque rating? High quality Moser 31 spline axles have a 7000 pound rating.

customblackbird

iTrader: (15)

first here is the car craft article on the ford 8.8 swap, talks about strength of the ford 8.8 compared to the 12bolt.
http://www.carcraft.com/techarticles...end/axles.html

as far as strength of the 12bolt and ford 8.8... they are almost identical rears.... same ring and pinon size etc. the only diff is the stock axle size which is the weak link. the ford 8.8 being 28 and the 12bolt being 30.... but as i stated the newer ford 8.8, 95 and newer got 31 spline axels so they are stronger than the 12bolt. in 97 the ford 8.8 got rear disk brakes.

im not sure about the tq arm mounting. but currie sells the tq arm mount as a BOLT on for his 9bolt rears.... so it is prob gona be just as strong as welded on im guessing. still tho i am weary of welding to the cast iron but maybe a bracket can be made and can be welded to the axle tubes with a brace of sum sort. id like to see wat shagwell has done. that seems to be my only prob.

as far as the specs go for the 31 spline axles i pulled them off a JEEP forum where a guy did a ford 8.8 swap from a 97 explorer into his offroad jeep and he had all the specs. but i would expect only a small increase in strength from an aftermarket brand. same idea as grade 8 bolts, 150,000psi rating. ARPs next line up over the grade8 is 170,000 and there best line is only 190,000-200,000psi rating. thats not that much of a huge diff. the 150,000 grade 8 to the 170,000 psi rating of there strong racing fastners is only a 1.13% increase in strength. and there best bolts are wat a 1.33% increase in strength. so i guess the 1.07% increase in strength from the moser axles compared to the stock 31spline 8.8s is about right on.

honestly i think the currie/moser/strange bolt in rears are a waste of money and are overcharging out the arssss. no way 2400 is a good price. who cares about the fab work etc its not that difficult. posi/locker is wat 400-500$ gears 150-200$ axles 200-250$. so there charging 1400 for the installation/bears etc and the case? thats alot of $$ to pay. a ford 8.8 swap will cost me maybe 600$ if its in good condition and has the gears i want. they even say in the article how much u can save with a swap.

big gear head

The 12 bolt has a 30 spline pinion and the 8.8 has a 28 spline pinion. The 8.8 is not stronger than the 12 bolt.

Before there were bolt in 12 bolt rear ends for these cars someone fabricated a bracket that bolted onto the rear of a 12 bolt. This bracket was cut out in the shape of the cover gasket and bolted on between the housing and cover. It has mounts welded to it that mounted the torque arm. Seems like it had something that clamped around the pinion snout too. I would feel better about this than something welded to the cast iron.

AlkyIROC

The Currie mount is designed to be welded to a 9" housing. The 9" housing is stamped steel and much easier to weld onto. An 8.8 or any other diff won't have the same dimensions to properly fit the Moser bracket.

You can easily and cheaply install an aftermarket 9". You buy the housing and axle package with 31 spline axles for about $1000. A big chunk of that is just for the axles. Buy a center section from the junkyard with a 31 spline carrier. If you're lucky, you may find one with a good gear ratio and a posi. I picked up one from an old Bronco with 4.10 and a posi for less than $100 once. You install your brakes onto the 9". The axles will already have the Chev lug pattern so your brakes and wheels will fit.

Simple 9" bolt in installation for less than $1500 and no fabrication required.

customblackbird

iTrader: (15)

states here that the 8.8 is identical to the 12bolt in almost every aspect. except the axles are 28 compared to the 12bolts 30. but that changed in 94 where they installed 31 spline axles and larger axle tubes. the only real diff between the 2 is that the 12bolts pinion is larger by .075".

http://www.carcraft.com/techarticles...ferential.html

i too am not to happy with just welding the bracket to the cast iron. i would like to see if more ppl have found a way around this and fabbed something up. i would def think of a way but i would like a place to start from. thats an idea to make one out like a gasket for the rear cover. maybe on the outside of the cover and not the whole perimeter (just a few like 4bolts or so and then fab something to go around the pinon snout.... pics would help immensly. i wonder wat thickness material i would have to use... hmm

i wish it where that easy stephen lol... around here in northern NJ there are hardly any salvage/junk yards. the best one that was in driving distance closed down thanks to the EPA. cars out the wazzooo and like 5 thirdgens. i went there alot.

big gear head

I'd have to go back to my '80s Super Chevy and Hot Rod mags to find pictures. It would probably take days to go through them and find it.

customblackbird

iTrader: (15)

i was reading older threads on this. and many ppl have come up with stuff that works but no one is able to post pics!!!! GEEZZ!

one guy had one on a 8.5" on his 3rd gen and he has a tq arm bracket made for a grandnational. said it bolted on like a spacer between the rearcover and center section and needed to use 1.5" studs and nuts/washers.

i just really need some pics to start from to see how hard this actually is. shagwell has done something like this, ive read it in older threads but no pics

AlkyIROC

Trying to do one of these swaps I always look at it this way.

If you have enough fabrication skills to fabricate a sufficiently strong torque arm mounting bracket onto a junkyard diff, you won't be asking how to do it. If you don't have enough fabrication skills to do such a job, you shouldn't even be attempting it.

It's not just you but that goes for many repair and modification questions asked on TGO. People asking how to fix something that they shouldn't be attempting to fix without proper knowledge etc.

customblackbird

iTrader: (15)

theres a diff between asking how to do something and seeing what others have done for ideas. i would have a design already if i had the rear in front of me. but i dont which is why im asking for pics. ive also never welded cast iron/cast steel before. i like to think about a project and take time to design something for the best outcome. always do my research before i buy/make something.

ull see that 8.8 under the rear and everyone who paid 2400-3000$ for a bolt in setup will punch themselves in the necks! u just watch!

Granny

I build 75 or so 8.8's a year for RX-7's, most with my own design torque arm, but i have also built the same general torque arm for 8.5 10 bolts as well. Here's a link to pics of my shop mule with a torque arm 8.5"... http://members.tripod.com/~grannys/GSSshopmule.html

The Explorer rear does have the big axles/bearings and 31 spline axles, but the pinion is offset quite a bit and it has 3-1/4" x 1/4" thick axle tubes and heavy brakes, quite a bit heavier (40 lbs or so) than the Mustang 8.8 that has 2-3/4" tubes. I prefer to use Crown Vic housings myself, lighter centersection and thinner 3" axle tubes. We narrow the housings and put custom 9" axles/bearings in them anyway, so their wider width does not matter to us. The Crown Vic housings are also easier for us to find, as the Mustang guys are not buying them up. The Crown Vic disc brakes are a lot lighter than the Explorer's too.

Here's a list of narrow rear widths that can be built cheap using stock axles, but some will require narrowing the axle tubes...
53-1/4"....using 2 right side axles from a Ranger (28 spline)
56-1/8"....using 2 right side axles from an Explorer (31 spline)
59-1/2"....stock FOX mustang width, using left side axles from a Ranger (to get cheap 5 lug)
Other combos are possible, but those axles are not as easy to come by cheap.

All the above are 5 on 4-1/2" and use equal length axles, which results in 1/2" of pinion offset (passenger side). The stock Ford 31 spline axle's diameter at the bearing is even bigger than that used by the typical 9", and is really a pretty good axle. The Ford 8.8 uses exactly the same pinion and carrier bearings as the Chevy car 12 bolt, with the 28 spline axles being weaker than the stock 12 bolt axles, while the stock 31 spline Ford axles are stronger than the stock 12 bolt parts.

Granny

Granny

Here's a link to pics that show my TA a little better... http://members.tripod.com/~grannys/solidaxle.htm

Granny

customblackbird

iTrader: (15)

wow tons of good info there granny. i actually saved like 4 pics of ur tq arm setup as a guide about 4hrs before u posted this lol. that stuff looks amazing, alot of time and planning went into that.

so u suggest the crown vic 8.8s... hmm i didnt even consider them. i really wouldnt want to have to cut the tubes and shorten them etc since ive never done that or have the knowledge/tools to pull something like that off. still tho what do the crown vics come with stock? say i was to pull one out of a wrecked police car or something? i dont mind having to change over the stock coilbrackets/LCA brackets to it thats not a big deal for me. but whats the total length of the crown vic rear? and how much can they handle stock and upgraded?

i heard it was bad to use axles from the same side like 2 right hand axles bc the axels are stressed to that one rotational direction and when put in a position say on the left hand side of the vehicle there is an increased chance of snapping the axle easily.

the stock 9bolt i have is estimated to be about 62-62.5" length from rotor to rotor. so what would i have to do to get the crown vic to fit? so a crown vic 8.8 with explorer axles would work? both the posi would have to be 31spline tho to fit the explorer axles right? or are the crown vics 31spline?

but just asking how much do u sell crown vic beefed up 8.8s for? say with 31 spline axles and a strong posi (would love a locker but street driving will suffer) with disk brakes?

thanks for chimming in and providing great info, really appreciate it! as well as confirming that im not CRAZY with my provided info.

Granny

The Mustang 8.8 supply is pretty dried up for around a 50mi radius of the shop, but there is a Taxi Cab wrecking yard in Seattle where we can buy several Crown Vic units at a time, saving us a lot of time hunting for housings.

The Crown Vic/Lincoln Mk7 8.8 is 61-13/16" wf/wf and 28 spline. Early ones have drums, but the later ones have disc brakes w/ a small mini-drum style e-brake inside the rotor. They use the same caliper and mounting bracket right and left, so one caliper sits ahead of the axle, the other side is behind.

No easy/cheap way to get a light 31 spline rear. The car housings all have the small outer bearings, so explorer axles will not fit unless the you install explorer ends on the tubes. You can buy pretty inexpensive aftermarket 31 spline upgrade axles for the FOX housings though, just look in the Mustang magizines for the good deals on axle packages, but.... 31 spline upgrades to FOX housings also require a 31 spline diff, which has a larger 7/8" spyder shaft (vs 28 spline's 3/4" shaft), so simply replacing the axle gears in the TracLoc is not an option...the whole diff will need replaced.

We get $1925. for our cheapest version of the 8.8 that bolts into the stock '79-'85 RX-7's suspension points, has custom 31 spline axles but c-clip retention. The Torque Arm version is $2525., and is a hybrid w/ 9" style axles/bearings. Not cheap, but it's a bolt-in solution for my RX-7 customers. I wouldn't sell them any cheaper, as there is a lot of time in prepping the housings in addition to all the new parts. We buy complete rearends for the builds, but all we use is the bare housing. Everything else is brand new.

I've actually done some testing on the axle swapping question, although it's not something i can quantify for this specific situation. Here's what i found...if the axles twist just enough to take a permenate set, they actually work harden. They were less ductile, but they did have more resistance to twisting in the opposite direction. I have had axles in a smaller scale application where we were actually twisting them to the point of failure quite often, with no immediate upgrade solution. Then we tried switching sides when we reached 1/4 turn of twist along the shaft. The axles would never twist back to 0, and we never broke any of those that were "pre-twisted" except for cases of crash damage. For our purposes, the reversed axles were actually stronger. My opinion is, if you are not permanately twisting axles, the swapping of sides is not something i would be concerned about. If you are twisting them enough to take a set, their properties will change, depending on how much they are abused. If the twist is concentrated in one area of the shaft, i would definately not re-use that axle.

Granny

customblackbird

iTrader: (15)

again granny thanks for the info. seems like the crown vic 8.8 seems to be the best choice. close to stock specs (length). if i were to get a crown vic 8.8 wat years did they start with disk brakes? and the better years to get (strength etc)

what i would like to do is get a crown vic rear with disk brakes.( im not using the ebrake on my car.) get the rear and replace the axle with prob moser 31spline axles(5lug) and then replace the diff im guessing for a 31spline axle. any idea on costs for a 31 spline diff? what parts would i have to get individually to replace the diff? none of the crown vics ever came with 31spline axels?

if i were to keep the 28spline axels but upgrade them to better moser/strange axles wat is the expected HP output of the crown vic rear? sry for all the questions. looking for a cheap alternative for the 2400$ bolt in moser/currie.

im glad to hear that with the axles. from what ive heard this is a nono but maybe i would consider it now. how can u tell if the axle are twisted in a concentrated area vs a wide area?

big gear head

Granny, that's some great looking stuff that you have. Looks like some high quality fabrication and engineering.

Granny

You can find used 31 spline TracLocs from Explorers on craigslist from time to time, as those guys occasionally want to switch to lockers. It might even be cost effective for you to buy a complete Explorer rear for the gears and diff if you are on a budget, as it's easy to find them with 3.55/3.73/4.10 gears and a TracLoc. Just look at the tag under the rear cover bolt to find the original ratio... it will read "3 73" for an open diff w/ 3.73 gears, "3L73" for 3.73 gears and a TracLoc.

A new 31 spline TracLoc can be had for around $300. A 3 pinion Detroit TruTrac torsen style is around $425, and a Detroit Locker is about $600. Spools are only about $150, but require 9" ends or c-clip eliminators. Randy's Ring and Pinion is my favorite source for new parts because they are reliable and next day for me, but deals are out there. just look at the ads in the Mustang magazines.

A poorly designed axle will typically twist at it's smallest dia near the spline, concentrating the stresses there. A well designed axle will twist along it's entire length, like a torsion bar. If you see twist along the splines, do not use the axle. Consider that in the Mustang world they drag race extensively using the 8.8 w/ equal length axles, which are easily interchanged side-for-side. I've never heard of anyone worrying about getting them mixed up.

I can't remember when they started using disc on the Crown Vic, but i'm thinking mid '90s.

Granny

customblackbird

iTrader: (15)

thank you granny. ur the man.

so really all i need is altermarket 31spline axels, a 31 spline tracloc. and my gears of choice correct? id rather a tracloc due to the car will have alot of street miles when its done and lockers are scary on the street and spools are just dangerous lol. id like to do this cheaply so i would love to just drop a rear in and call it a day but car will be a high11 on motor and prob low11 on juice or if i build a turbo down the road. u dont think a stock crown vic 8.8 with stronger 28spline axles would u hold up?

i thought u said i couldnt fit the explorer 31splines in the crown vic rear? that the axle ends are too big and i would have to fit the explorer axle ends and bearings on the crown vic tubes. i believe u with the mustang world racing the ford 8.8s. my friends 88 mustang FX has a stock 8.8 with 3.73s and with a 150shot hes in the high 11's. no probs with the rear so far. and he has the small 28spline axles since they are stock. i will keep a look out on the axles tho as far as the twisting.

big gear head

Eaton also makes a 31 spline posi for the 8.8. It's better than the Traction Lock, but more expensive too. The Eaton can be tuned for your needs. If you drag race a lot it can be upgraded with more clutch discs and stronger preload springs. It can also be softened up, but I don't know why anyone would want to do that.

Granny

The Explorer rear could be a cheap donor for the 31 spline diff and ring/pinion. All the 8.8 carriers have the same overall dimensions and are able to fit all the ratios...there is no "case split" like the GM rears where certain carriers can only be used w/ certain ratios. As long as an 8.8 diff has the correct spline count for your axles, it can be used in any 8.8 housing with any 8.8 ring/pinion set.

The aftermarket axles are needed because in your case they would need to fit a 31 spline diff, but fit the small passenger car bearings that are used on the Crown Vic housing.

I agree with the choice of a TrackLoc for for the street. They are an inexpensive choice that is much safer than a locker in bad weather. It can be tuned...packed like stock, or more aggressively to the point that that it's they act like a spool. It's all in the pack sequence and pre-load for the TracLoc.

Granny

customblackbird

iTrader: (15)

great so now i just need to find a place that has rears for cheap. any way to tell if the posi is worn at the place? i heard about putting a tq wrench on one side and then have someone spin the other side. if the wheel with the wrench can click the wrench at 35ftlbs then the posi isnt worn that bad. the higher the number the better condition of the posi. does this apply?

my ideal situation would be to find a crown vic rear with disks. and a good posi, then swap out the axles for 5lug stronger moser axles. but if i can get one cheap enough i would just replace the posi and throw in a 31spline posi/axles of course right there im at 500$ for posi and 250$ for axles.

how much power could a stock 28spline crown vic rear take with stock posi?

mcgarnicle

iTrader: (14)

I think your cheap alternative rear is kind of a bad idea. No offense, I think if you want a beefed up rear with little to no fuss is to go with Stephens plan. It's stronger, less hassle, and I'm envissioning less money also.

Batass

I followed Stephen's advice as well. I picked up a housing and 31 spline axles for 1000 bucks new, and installed a third member for 200 bucks. I have a near bulletproof BOLT IN 9" for 1200 bucks. And my LT1 disc brakes bolted right up.

If I were going to go with ladder bars, perhaps I would've gone with an 8.5" or an 8.8.

customblackbird

iTrader: (15)

a 9" would be a better choice no doubt but they eat a bunch more HP vs the stock 7.5" or ford 8.8. they are stronger but come with a bigger penalty. they are also wayyy more expensive around by me if u can even find one. the 8.8 is close to the strength of the 9" and will let me get more of my power to the ground. its a good choice and a great plan by stephen. in northern NJ there arent any real pick your part salvage yards anymore. i cant even find things on craigs list or ebay around me.

also how many ppl have 8.8s in there cars? no one. id like to be one of those ppl that can say, HEY u can do it bc i did. if really the only thing thats gona hold me back is to fabricate a bracket for the tq arm then thats really not a big deal. what i have is more time and not alot of money. and if mustangs can run 10-11s on stock 28spline axles/stock posi then i think thats a good rear. so maybe i spend 900 on a 31spline ford 8.8 that i could never break and u spent 1200 on ur 9" and i'll have less drivetrain loss.

i strive to be different.

Batass

It does eat more power. I don't know how efficient the 8.8 is but the S60 would have given me about 17 more hp to the tire. A 12 bolt would've been like 8hp more. I'm also making 700 crank hp. If the 8.8 is as efficient as the S60 you might notice the power, but I doubt it.

I got my third member from ebay. 40 bucks shipping.

I'll be putting an 8.8 in my S10, but everyone does that.

If you're striving to be different well then hell yea, but I thought you were going for cost effective.

Granny

You can get a general idea of the condition of a 8.8 TracLoc by measuring the axle endplay. As the clutches wear, endplay will increase. Anything over .035 is pretty loose..i like to see it .025 or less. I have shimmed them to .005 during rebuilds, not to increase pre-load, but to reduce the brake pad knock-back. Road racers like the pads close to the rotors to reduce brake pedal travel.
Breakaway torque could be used as an indicator of clutch condition, but the composition of the lube can have quite an effect. Friction modifiers are typically added, but maybe not, maybe 1 bottle, maybe 2...but who knows unless you were the last one to service the rear. There are also lighter/heavier pre-load springs that can have an effect on breakaway.

Tests have shown the typical 8.8 gearset to be about 3% more efficient than the 9"...thats 15hp you are giving away (assuming 500hp) unless you really need that extra strength. Unless you put a bunch of money in the 9" for aluminum parts, the passenger car 8.8 is going to be quite a bit lighter too.

Another thing to consider is where you plan to run and how fast you plan to go. At an NHRA track, i believe it's mandentory to have aftermarket axles and c-clip eliminators to go quicker than 11.00 in the 1/4mi.

Granny

Batass

Well, take some good pictures, document it well, and record your price list. If it comes out on top, then awesome! Might make a good sticky! I think it'll come down to the strength of the welded cast area.

Granny

Our design does not require welding to a cast area.

Granny

Batass

Oops, I don't know what I was thinking.

customblackbird

iTrader: (15)

thank you granny. where would u test the axle endplay? are u talking about the splined part in the pumpkin or at the end of the axle by the brakes? great info. ive also heard that rule about c-clip eliminators. im gona have to look that up. personally c-clips are dangerous on a street driver. snap an axle and ur wheels coming out lol.

i read a article on where they tested all the rears available on some car(cant remember the car) it was an old car tho. they tested the dana, ford 8.8 and 9", 12bolt, 10bolt and something. they were testing for which rear eats the most power. all on the same car in the same day. they found the dana and 9" eat alot of power (due to the offset pinion) then the 12bolt and 8.8 where next. they ate less power which meant u got more power to the wheels but the smaller 8.5" 10bolt required even less power to turn. this basically means just build the rear to handle what your gona throw at it.

a car with 500hp doesnt need a 9" or a dana, and a 400hp car doesnt need a 12bolt. same goes for an engine... u dont want to throw the biggest cam u can into an engine it should be matched to the heads/intake.

batass... i was planning on going the cheapest route.... so who says being different and cheap cant coinside? 8.8s are everywhere in a junk yard. cheaper than most rears besides our stock 7.5" and are wayyy plentiful. cost could be just the rear which can be had for less than 200$ if the posi is good. As stated i will be mixing designs from grannys beautiful tq arm setup as well as this (see pic) i believe its spohn.

something that bolts to the bottom and top of the rear cover like in grannys but has the same tq arm mount as in the pic below. a welded peice will also fit around the smaller end of the pumpkin by the driveshaft. 3/16" steel i think would work nicely and could be a bolt on

kind of a mix of the three pics but that bolts to the top and bottom of the rear cover.

Granny

If the calipers are removed, it's easy to measure the distance from the caliper bracket to the rotor...measure with the axle pushed in, then compare that to a measurement taken w/ the axle pulled out. The difference between the two measurements is the axle endplay. Both sides should be checked.

I personally have little concern about a c-clip axle coming out if the rear has stock disc brakes. My opinion that it's mostly an outdated rule that's in need an overhaul, probably left in place to patronize series sponsors.

Another fab possibility is a stepped plate welded to the driver's side axle tube, located right next to where the tube meets the housing. Clevises could be used instead of rod ends...i'll attach a pic of one of my torque arms for the 3rd gen RX-7, which uses a similar clevise scheme.

Granny

customblackbird

iTrader: (15)

ok. i understand the end play measuring. thanks. and i'll spread the word about the c-clips lol.

i like the clevis idea it kinda makes it easier to fab something up. wouldnt the tq mount not want to move tho on the housing? dont the rodend/clevis allow movement? i look at the stock mount and i see that the tq arm mount being cast into the pumpkin that it isnt suppose to move. wouldnt that pic i posted of the red spohn mount allow the bracket to move? compared to like how your fox body tq arm is solid with the axle.

i was also thinking of doing it around the tube but that would put alot of stress on one tube unless i did both sides. i figured a bolt on tho that if something happened with the housing that i could use the tq arm mount again on another housing.

i was looking at clevis ends and where i got my tubing from its wayyy expensive. what i need to find is a cheap place online to get 3/16" mild steel plate and tubing from. know any places? places that will ship it? all of my iron works up here sell in huge bulk like suppliers.

big gear head

Be careful about using the axle tubes for a mount. The tubes are plug welded into the center casting and can break loose. This is a big problem on the first and second gen Camaros where the whole suspension is mounted to the tubes. The plug welds break loose and allow the center to rotate up and crash into the floor.

Granny

The torque arm's purpose here is to control the up/down action of the rear's nose. It won't control side/side movement or push the car down the road. A stamped torque arm will be sensitive to a less than solid mounting point, but a tubular arm could even use rod ends for attachment if designed properly.

There is a place in Seattle called Metal Shorts that sells custom cut short pieces of tube /plate/etc. Here's a link to their contact page... http://metalshorts.com/contact_us.htm
They have no problem selling to hobbyist machinists that only need small quantities.

The 8.8 guys have the same plug weld issue, but with the torque arm bracket picking up the pinion area of the housing for support, i doubt it would be an issue here.

Granny

big gear head

That is what I was talking about, the 8.8 plug welds. I was just warning against welding the torque arm mounts to the tubes. They need to be connected to the center casting somehow. A bolt on mount like the one you built would probably be best.

customblackbird

iTrader: (15)

yes im sry i forgot to mention that the first thing i would do is weld the tubes all the way around. thats the first mod that should be done to almost all stock rears.

yea my tubular tq arm is the jegster. see attached pic.

im def gona have to give them a call. thanks granny. i was looking at this place last nite. hows this look a 12x12 hot rolled sheet of 3/16" steel for 22$

http://www.onlinemetals.com/merchant...=839&top_cat=0

Granny

I weld the tubes to the housing on my torque arm setups only if a customer specifically requests it. Housing material is listed as ductile iron, so nickel rod is used. On torque arm rears i build for my personal use, i do not weld the tubes to the housing.

Not a bad price for a speciality supplier. As a ref point, at my local steel supplier here in WA state, 3/16" hr plate currently costs around $8.75/sqft if it is sheared into a size smaller than a full sheet, but that's for a walk-in customer...no freight or packaging costs.

Granny

customblackbird

iTrader: (15)

hmm thats like triple what u pay... looks like i got some more searching to do lol. what if u bought me sum and then shipped it to me? id pay for the shipping and costs of material obviously. just a suggestion.

why dont u weld the tubes on your setups? are the plug welds weak? this is a common problem with the stock third gen 7.5" and this is usually a first mod for most aftermarket performance buildups. moser, strange, etc etc. they all weld the tubes. in any tech article ive seen as well as the carcraft i posted above did it as well.

im gona do some drawings and see what i come up with. and post them and see what you guys think.

Philerup

Intresting subject matter here,LOL. Myself if i'm going to build a Ford I build A Ford, a Mopar a Mopar,and A CHEVY A CHEVY. LOL. Though I'm always fasinated with customization and modifacations.

Batass

Thats what narrow minded people say. I'll take a lightened fox body with a 6.0 any day.

So when you build a chevy-chevy, do you use all genuine chevrolet parts?

big gear head

The first and second gen Camaro rear ends are completely supported by the leaf spring mounts, which are on the axle tubes. All of the torque is transmitted through the tubes. The third gen Camaro has the torque arm mounted to the center casting. All of the torque is transmitted through the center casting into the torque arm. None of the torque is transmitted through the tubes. There is no twisting motion in the tubes, so the plug welds are not in danger of breaking. There is little need to fully weld the tubes in the third gen Camaro rear ends.

In the FOX Mustang and Chevelle about half of the torque is transmitted through the tubes and the other half through the upper part of the center casting. The need is not as great to weld the tubes in these rear ends as it is in the early Camaros, but there is still some need to weld them.

Granny

Big gear head explained it pretty well. With most torque arms, the typical tube twisting forces are greatly reduced....cost/benefit ratio (to the customer) of the tube welding mod, in this case, is pretty poor.

Granny

andrewmp6

I'm a ford guy and i won't use a 8.8 again i snapped one in a ranger i had.The 408w i had and slicks kill it in 2 months.A 12 bolt is a little bit stronger then a 8.8.If you do it tho the cobra rear brakes are 11 inch single piston best bang for the buck is the police crown vic rear brakes they are vented disc.

Granny

The 12 bolt is stronger than the typical Ranger 8.8...30 spline 12 bolt axles vs 28 spline for most Ranger axles.

Many modern axles, including GM and Ford, are "24 pitch", meaning that a 24 spline axle would be 1" in dia...adding splines to the count will increase the axle's dia, increasing it's strength as well. A 30 spline 12 bolt axle will be stronger than a 28 spline 8.8 axle. A 31 spline 8.8 axle will be stronger than a 30 spline 12 bolt axle, assuming the same alloy. Ford's axle material is listed as "1050", pretty good stuff for an oem, while GM is listed as "carbon steel", which usually means the more common 1040.

Don't get me wrong, i like the GM car 12 bolt too, but the 8.8 is much easier to find, and cheaper to build.

Granny

andrewmp6

I had the 8.8 out of the explorer which is 31 spline and a min spool in it.It lasted about 2 months of drag racing it every week end i won the street class 3 times.A 12 bolt isn't that hard to find would have to be shorted tho.How wide is a mustang 8.8 compared to the 3rd gens width.To me the 3rd gen seems wider but could just be me.

big gear head

The Mustang housng doesn't have 3 inch axle tubes. The others are stronger.

customblackbird

iTrader: (15)

crown vic has larger tubes. the explorer being the largest and thickest are also the heaviest.the mustangs overall length is also shorter the stock 3rd gen width. the crown vic is actually really close to the width of a stock 3rd gen rear.

i am looking for a newer crown vic with rear disks.... prob out of a wrecked cop car.