8.8 fitment in 66?

[XXBULLETSXX]

Any one know if an 8.8 rearend fits into a 66 Fastback without any modification? I'm thinking that it will have to be narrowed and I have no idea how much that would cost.
Going 8.8 maybe a cheaper solution that tracking down a 9", what do you guy/gals think?

 

[Red5oh]

It all depends on the wheels. I have an 8.8 in my 67 with 1.25" spacers, but 05 wheels... so, what wheels do you have?

 

[Ronstang]

The explorer rears will work with some minor mods. I have 3 of them to use as test mules to see what the mods are like. The nice thing about the explorer rears is they have 3.70 gears, trac-loc differentials, 31 spline axles, and disk brakes. I will not get to converting these until late Aug of Sep but if you are not in a hurry I can let you know. I can get all of the explorer rears I want, I have a local source.

 

[66Runt]

Which one?

There are a bunch of choices for an 8.8, really depends on what your overall design parameters are.

I used the 8.8 out of a '91 Mustang GT. It is 2.5" wider than the stock differential (1966 Mustang). The reason I went this way is it is lighter than the other 8.8" rears. You can run a light weight disc brake setup (Cobra 11.65" disc brakes) and have an operational parking brake, without the excess weight of the explorer drum parking brake system.
Over all it makes a pretty significant difference in unsprung weight.
If you want to maintain the stock wheel spacing without narrowing the rear, you would need a 5.75" back space wheel (i.e. late model mustang).

Good luck,

Scott

 

[nugget68]

what about an 8.8 out of a ranger. i have one out of a 2001 edge w/ 4.10 gears and a locker. it seems that the pinion is off set more than the 8" in my stang, its a 68. i wanted to try and put this in my car but i was afraid that with the pinion being offset it would maybe cause my drive shaft to hit the floor, where it wouldnt be exactly centered in the tunnel. what do you guys think?

 

[tommytorino]

I have an 8.8 in my 67

Ok Ill bite.... 8.8 has an offset pinion.... how did you align the rear in your car?

Im looking to perhaps use a fox mustangs 8.8 in a 65. I understand the 8.8 will be wider, but I seem to recall the pinion is offset.

Man, what I would give for a step by step somewhere on the net for this swap!

Thanks

Tommy D in NY

 

[D.Hearne]

There are no 8.8's that are direct bolt in's for an early Stang. By the time you narrow one and have the brackets welded and buy new axles, you've spent the same money that narrowing a 9" cost. The Explorer/Mountaineer is the best 8.8 to start with. Most(not all) have 31 spline axles, gearing varies, most are either 3.73 or 4.11's, some have drums, some have discs. You still have to move the spring perches to work and address the 4" pinion offset. The Ranger rear has the same dimensions as the Explorer, but the perches are flipped and they've got 28 spline axles (99% of them anyway,I've heard of a few 4wd's that got 31's) and the same small brake backing plates that the late Stangs had.

 

[wildstang]

Not quite all true D.Hearne, the Ranger 8.8 is narrower than the explorer. The 91-92 rangers are 3" narrower, then I believe in 93 1.5" was added to them so they are only 1.5"s narrower then the explorer. I also think that the FX4 rangers got 31 spline axels in the 8.8. All this info is available at ranger station in the tech library.

Another option of dealing with the offset is to the shorten the long side of the axel (if it is on the opposite side of the offset) and then find another short axel. This way you might be able to center it by adjusting the spring and shock mounts. When people convert fox axels from 4 lug to 5 they can use the short axel from rangers for both sides of the fox 8.8, they have the same 5 bolt pattern and are 28 spline. I also have read or heard that the axels in ranger 8.8 and 7.5 are interchangble, same axel same strength and spline.

 

[D.Hearne]

I bought a 94 Explorer rear for my 89 Ranger and it was the same dimensions as the Ranger 7.5. Only the spring perches were flipped. And it was the same width as the 90 8.8 I had in the Ranger after the 7.5"

 

[xoxbxfx]

ok...i have experience and dealing with this crap right now.

I have already installed a 8.8 from a 2003 GT. Its a pita to cut off the upper and lower control arm brackerts and you have to weld in spring perches. The ONLY reason I did it was because the rear and spring perches cames with the car and I didnt have to buy anything yet.

With bullitt wheels (pre-05) the wheels stick out about 1.25" on each side. I rolled the fender lips and am still 1" off. Im having the rear end narrowed 3 inches and axles cut and resplined. The foxbody rear ends are 1.5" narrower but still not enough to run 94+ wheels. To do it, you need to run a fox rear end with 05+ wheels becaues it has a positive offset of 44mm I believe where 94-04 wheels ahve a 24mm offset. So with a fox rear and 05+ wheels, you can suck in the wheels about 1.5". I still think you would need to roll the fender lips to make it "safe"



Ronstang - any chance I could get you to measure the short side axle tube on the explorer rears?? Im wonderin if I used 2 explorer short axles if it would be what I need. I need 1.5" shorter axles


PICS

View attachment 457696
View attachment 457698

 

[D.Hearne]

I don't recall which side this axle came from but the remaing axle I have from the 94 Exploder rear is 30-5/8 from the outside flange the wheel sits up against to the inside end that buts up against the differential cross pin. I think this may be the long axle. I think I sold the short one to someone else here doing an 8.8 Exploder swap.

 

[66Runt]

When using the Mustang 8.8 it's easier to use the Fox body version

Setting it up is pretty easy. Took me a little over 8 hours to cut off the old brackets, line up and weld the perches, paint the axle housing, build the whole thing from scratch (it was a bare housing, I added a 31 spline True-trac, Superior axles and FRPP 3.55 gears and girdle), and install with the Cobra brake package.
The Mustang 8.8 does not have an offset. It is the perfect width for '67-'68, and '65-'66 with late model 5.75" bs wheels. The housing uses 2-7/8" diameter tubes, and smaller end caps then the Ranger and Explorer rear. It's really a light weight, but strong differential, that is also more efficient than a 9".
If I was planning more than 500 ft/lbs of torque, I'd weld the tubes at the center housing, If I was planning more than 700 ft/lbs of torque, I'd build a 9".
I think people make a lot bigger deal out the difficulty level than it really is. A little common sense, patience and accurate measurements, and it's no more difficult than building any other portion of the car. It's a hell of a lot easier than body work
Not sure what problems or complications others have run into. The biggest issue I had was finding the information to correctly shim the carrier, w/o spending money on a bunch of exotic tools. That was as simple as a trip to the local library reference section.

Here's a shot bolted in
http://www.mustangforums.com/upfiles/16598/369B316C969644799B7653F8A0EAE3A8.jpg

And here's a shot from the side with the 4.75" bs wheels.

http://www.mustangforums.com/upfiles/16598/20573526C7F84A779FA992A15CCAC618.jpg

Again this rear housing is from a '91 GT.

Good luck,

Scott

 

[D.Hearne]

99% of the Ranger rears have the same small bearing ends the Fox and later Stangs have.

 

[66Runt]

Do you know what diameter the axle tubes are?

The reason I ask, is that if they are the same diameter (2-7/8") as the Mustang, that would be a good source for U-bolts. I ended up sourcing U-bolts through Napa. Also if they are the same as the Mustang, do you know the diameter and length of the U-bolts?
Thanks for the information!

Scott

 

[xoxbxfx]

After HOURS of research heres what I have come up with...

When using standard 94+ wheels and 8.8 in a stang here is the following of what you want to do

87-93 = GOLDEN
94-98 = You have 2 real options.. 05+ wheels with a 44mm positive offset, or shorten the rear end 1.5" overall. It uses 29.12" axles. The best axle option for this method is fox axles. 79-93 mustang axles, 83-92Ranger left side axle, 83-91BroncoII left side axles.
99+ = Shorten the rear end 3" overall and use the same axles as 94-98 setup would.

Basically you are after a 29.12" axle

How I figured it... With the 66 Im working on (pictured above), the rear end needs to come in 3" overall, 1.5" on each side(with rolled fender lips...but should clear the fender lips). The tires stick out 1", so 1.5 should be safe. Its a 2003 rear end and uses a 30.62" axle. 1.5" on each side makes it a 29.12" axle, which makes it perfect. Doesnt seem to happen often.

 

[D.Hearne]

So if you happen to have a 2003+ 8.8 and want 31 spline axles for it, two long side Explorer axles are what you need. (if that's a long Explorer axle I still have)

 

[96 DOHC Cobra]

So if you happen to have a 2003+ 8.8 and want 31 spline axles for it, two long side Explorer axles are what you need. (if that's a long Explorer axle I still have)

The length would be about right, but the Explorer axle won't fit the late Mustang axle bearing.

 

[96 DOHC Cobra]

By the time you narrow one and have the brackets welded and buy new axles, you've spent the same money that narrowing a 9" cost.

I think you will spend about the same on labor. I think the difference will be what you spend on donor parts mostly. There are tons of Explorers and Fox/SN95 Mustangs in wrecking yards. Finding one with five lug axles, discs, decent gears, and traction lok is easy and fairly cheap. Finding a comparable 9" rear won't be easy and not likely cheap. Also, if you're going to custom axles in the 8.8" versus stock axles in the 9" there'll be a significant cost difference.

 

[D.Hearne]

Well the 9" choices are similar, although getting scarecer by the day. If I wanted a posi 9" I'd limit my hunting to 4wd pickups and Bronco's. The cost of new axles is the same in any case. I paid $380 for the axles, bearings and bearing housings doing the 8.8 for the Ranger from Strange (and they screwed up the order) The price of 9" axles is no different. Same axles. You can buy cheaper axles for both, but not for custom applications. I put new Superior Axles in my 95 E150 last year and they were like $95 each.

 

[wildstang]

D.Hearne I don't know how that happened but I have 92 ranger with factory 4.0 V6 and 8.8 and a 91 explorer and I have measured them and there is definitely a difference in width. The front 4x4 front seemed the same because I couldn't really measure any difference.

I think the ranger station is a good source for some of these questions, especially the tech libriary, there is a lot of write up on these rears and identification. I actually have a 92 explorer rear out back, I will try and measure it for offset.

When SN65 built thier car on the 03 cobra chassis, they had to extend the fenders to accomedate the wider stance, they welded on the actual 03 cobra fender flares.