sn-95 8.8 rear in 67 conversion

[rompinstompin67]

Hey folks,

Its been a long while since I have been on here, but I am back. I took a three year break in working with my stang to get into nothing but trouble riding sportbikes... Young men and sportbikes is a bad idea. I was also unemployed for a little while, but now I have a decent job and nearly no debt left. So I am back to my Stang (I just couldnt sell her, even if it would have made life easier).

That out of the way, this may be a repeat question, but I have heard that a 94-95 8.8 rear end out of a sn95 has the same dimensions as my 67 9 inch unit and can be swapped in easily. Is this the case? I have a 9inch open right now with stock gears and drums, so an 8.8 traklok with a better gearing setup would be nice, and probably cheaper? Does anyone have the lowdown on this?

Thanks

 

[Red5oh]

I did a 91 8.8 conversion in mine (because I had it laying around) and it was fairly easy. I have a writeup of it on my cardomain site, so check it out and let me know if you have any questions, etc. Good Luck

 

[brianj5600]

I used a 95 GT in mine. The housing is actually a fox. Fox and SN95 housing are the same part so I swapped axles and brakes. I used the yoke and companion flange from the 95 and had a 50.25" driveshaft made with 1330 ends. I cut the brackets off the tubes with a grinder with a cut off wheel on it, followed with a grinder. The tubes are an odd size, I think 2.875". I used 3" tube perches. The Mustang leafs use a smaller pin than most perches come drilled for so I welded them up and drilled them smaller. I set the pinion angle the same as the 6cyl rear end I pulled out. I think 3* down?
The brake lines are different on the 8.8. The 8.8 soft line is center mounted, instead of offset like our cars. I used a stock 67 soft line and made hard lines to run to the calipers. I would probably drill and tap the tube and use a stock vent to secure it. I have not hooked up e-brake yet so I can't help you there.
To convert to 5 lug look here. http://mjbobbitt.home.comcast.net/mustang/5lug.html I bought 2 Ranger axles mentioned in the link from a JY and everything went together perfect. You can also put 9" ends on the 8.8 and ditch the c-clips. I have not done this yet, but is planned. I have heard that 9" axles are the same spline, but can not be positive.
The traction lock can be beefed up by adding an extra friction disc. There are threads in the fox section of this site that discuss it. Basically the stock set up has extra steel plates stacked together and you eliminate one of the steels for an extra friction. This site has some on it. http://www.angelfire.com/theforce/5o...5ohtech018.htm.

 

[96 DOHC Cobra]

The 94-98 Mustang rear is closer (dimensionally) to 71-73 Mustang rear. The Fox Mustang (79-93) rear is the same width as the 67-70 Mustang rear at 59 1/4." Nothing wrong with the 8.8, but if you already have a 9" rear, you'll be better off just getting the pumpkin and gears you want for it. By the time you buy and modify an 8.8 to fit, you'll have more money into it than your 9."

 

[rompinstompin67]

Hold on a second, I had a fox body car. They were 4 lug until 93 when the new body style came out. The 93 cobra had a 5 lug kit on it with rear disc. This is essentially the origin of the 94-95 8.8 cars, though it was widened slightly for the newer, wider body. The way I understood it, this was the 8.8 to get given its closeness in overall dimesions to the original dimensions of the 1967 mustang 9 inch I have.

Also, you get rear disc with the 94-95 junkyard swap. The earlier fox bodies had four lug drum on the back.

As far as I know, the axles on the 8.8 and 9 inch rear ends are NOT interchangeable.

I am not making a show car, just trying to make a cool street car. Right now I have a stock, open 3.00 rear with drum brakes needing to be redone. I just figured for a little elbow grease, some planning, and a donor rear end it might save me quite a bit of money.

 

[rhyno9]

Hold on a second, I had a fox body car. They were 4 lug until 93 when the new body style came out. The 93 cobra had a 5 lug kit on it with rear disc. This is essentially the origin of the 94-95 8.8 cars, though it was widened slightly for the newer, wider body. The way I understood it, this was the 8.8 to get given its closeness in overall dimesions to the original dimensions of the 1967 mustang 9 inch I have.

Also, you get rear disc with the 94-95 junkyard swap. The earlier fox bodies had four lug drum on the back.

As far as I know, the axles on the 8.8 and 9 inch rear ends are NOT interchangeable.

I am not making a show car, just trying to make a cool street car. Right now I have a stock, open 3.00 rear with drum brakes needing to be redone. I just figured for a little elbow grease, some planning, and a donor rear end it might save me quite a bit of money.

The 94-98 housings and earlier fox body housings are the same length. The axles are longer on the 94-98 to clear the disc brakes. The overall dimension of the 93 and older rear from axle flange to axle flange is either 1/4 inch wider or narrower than the 67-70.

I did the math on both of these swaps and ended up with a 9 inch. The big gotcha on the 8.8 is those c clips and 28 spline axles. Any decent amount of power and they both become a big problem. At that point the 9 inch stuff is cheaper and easier to build.

I really hate the smell of gear lube and I don't like redoing things so I decided to overbuild the rear axle.

 

[rompinstompin67]

yeah, I guess you're probably right.

 

[brianj5600]

The big gotcha on the 8.8 is those c clips and 28 spline axles. Any decent amount of power and they both become a big problem.

What is the problem with them? There are a ton of 10 second cars running them. Stock 8.8 stuff is not any weaker or stronger than 9" stuff. A friend of mine ran some 5.80's on a stock 8.8 with 4.30 gears. It was a time bomb for sure, but it lasted about 30 passes and was still going when he fianally upgraded.
I agree if you have a 9" use it, but I don't think it is stronger in stock form over an 8.8.

 

[rhyno9]

What is the problem with them? There are a ton of 10 second cars running them. Stock 8.8 stuff is not any weaker or stronger than 9" stuff. A friend of mine ran some 5.80's on a stock 8.8 with 4.30 gears. It was a time bomb for sure, but it lasted about 30 passes and was still going when he fianally upgraded.
I agree if you have a 9" use it, but I don't think it is stronger in stock form over an 8.8.

The big problem is when a c clip axle breaks the axle comes out. If you break an axle with 9 inch housing ends the axle is retained.

There will always be people that run things to the limit. Take your friend for example when he did upgrade what did he upgrade to? Did he go with a 9 inch? Did he beef up his 8.8? If he went with the 8.8 how much did the upgrades cost?

I guess my point is when I did the math I found that the 9 inch is less expensive to build because it has what I believe to be a stronger design due to a lack of c-clips.

 

[Red5oh]

I would say (and have vast experience) that the 8.8 w/o c clip eliminators is good to 450 rwhp. I didnt have any problems and just ran a good set of axles and a decent 3rd member.

They can be a very good setup if you dont overpower them. I have a basically stock 302, EFI conversion in my 67 and felt the 8.8 was a good choice. Not only for the price, but what it had to offer. It just depends on what you want out of it... I wanted a good daily driver... nothing more.

 

[brianj5600]

He bought a strange kit with 33 spline axles, spool and c-clip eliminators. He also bought a girdle. Total cost was about $800. The 8.8 should hold up fine now. For him to put a 9" in its place with the same stuff would cost more. If you google ford 8.8 it will bring up a ton of sites on how to swap one into a Jeep. They are plentiful, strong and cheap.

 

[Rusty67]

They can be a very good setup if you dont overpower them. I have a basically stock 302, EFI conversion in my 67 and felt the 8.8 was a good choice. Not only for the price, but what it had to offer. It just depends on what you want out of it... I wanted a good daily driver... nothing more.

That was very well said. People get hung up on what is better some times and fail to realize that some times it isn't worth paying x amount more for x% gain. For a daily driver with some modest power, an 8.8 is fine and if you can do the fab and install for the perches yourself you will save a lot of money if you can get an 8.8 cheaply.

 

[rhyno9]

Everyone in this thread has good points here. I think I may not have made my point clear so I would like to clarify myself.

I am not trying to say that the 8.8 is a worthless POS.

If the original poster had an 8 inch or the 6 banger rear end then the 8.8 is an attractive option.

What I am trying to say is when it comes to $$$$ the 9 inch will be cheaper for the original poster. This is because he already has the 9 inch. The soft costs associated with an 8.8 swap will add up quickly. Things like

Drive shaft modifications
Labor to weld on perches
New Brake lines
Will it need a brake job?
It's wider so will it require new wheels?

It's the "while I am at it" scenario that many people forget to include in the total cost associated with the swap.

If he can manage to scrounge up an 8.8 with the desired gear ratio and 5 lug disc brakes in the fox width that is in ready to run condition for under $250 and he can weld then the 8.8 could be a less expensive option.

 

[wildstang]

I read some where that the 8.8 is more efficient then the 9 inch meaning takes less power to turn the 8.8, so for drag racing every horse counts.

 

[rompinstompin67]

First of all, I am not arguing that the 9 inch is not the better of the two rear ends. If the 8.8 was better, youd see it in 60s scumaros like you do the 9 inch. I pick the 9 inch for drag applications any day.

Here is what I was thinking...

I have a welder and all the necessary tools for removal and refitting of perches..so worst case scenario, I buy a set of perches and modify them, also doable. Labor in this case is free.

I can fabricate the necessary brake lines and such as well, costing only materials.

Here in Sacramento, where mustangs are the beater of choice apparently, there are plenty of 8.8 5 lug disc brake rear ends floating around, some with gears already done or even a factory 3.27 set out of an auto car. Also, they come with a posi unit. They can be had for between $250 and $350 ALL DAY LONG.

So, since my 9 inch is 30 plus years old, is an open diff, has a 3.00 ratio, and drum brakes, the 8.8 seems like a deal for a driver car. I am not putting in a blown big block or anything, just a modest 331 or something. I was planning to do the granada conversion at the same time to get 4 wheel disc.

I figure the rear end conversion cost including sourcing the rear end should cost me $500 tops, right around the cost of a good limited slip alone.

Is this just the easy way out?

 

[Rusty67]

I totally see your point of view. To get the gears you want with a posi AND disc brakes, the 8.8 will be cheaper since you are doing the labor yourself. Save that 9" because maybe you will need it some day.

 

[rompinstompin67]

trust me, I will not be throwing out the ol 9in, I will be working on cleaning it up and putting it together with some nice parts, but for now, the car needs a lot of things and I just figured I know where there are a couple of 8.8 disc rears for cheap. Eventually I will probably go with the 9inch with a 4 link.

 

[rhyno9]

trust me, I will not be throwing out the ol 9in, I will be working on cleaning it up and putting it together with some nice parts, but for now, the car needs a lot of things and I just figured I know where there are a couple of 8.8 disc rears for cheap. Eventually I will probably go with the 9inch with a 4 link.

If you are eventually going to use the 9 inch how is it cheaper to spend any $$ on an 8.8 fox rear. It would seem to me that the money spent on fox rear could be spent on a disc brake conversion or center section for your 9 inch as you will most likely want those for you 4 link 9 inch.

If you will use the 8.8 for your 4 link project then it would make "cents" to me otherwise it seems like you are throwing money away by changing to an 8.8 and then switching back to a 9 inch.

I am probably the cheapest bastard known to man so I think about every dollar I spend on my mustang.

Obviously do whatever you want because it doesn't cost me a dime. I'm just saying I don't see the cost outweighing the benefit in this situation.

Good luck

 

[rompinstompin67]

I see what you are saying, but see I want to drive the car in the next ten years and on a state salary living in downtown....It will be a while before I can hook up the 9 inch. I am young and want to be stupid and drive my car, turn some heads. I will never sell this car. I have been through so much to keep it. It is my first car. That in mind, I want to do the 9 inch right, just not right now.

I have sourced an 8.8 too. It is a 95 gt 5 lug disc setup. The posi has the extra friction plate, new axles, bearings, turned rotors, new pads, and 4.10 ford racing gears. I am really not crazy about the 4.10 rear end.

My friend just wrecked his 95 so I will be getting his 8.8 for $150.00

either way, i dont have the time at the moment, but here in about a month I will be taking some time off to give my car some attention. Maybe then, but maybe not.

 

[rhyno9]

I see what you are saying, but see I want to drive the car in the next ten years and on a state salary living in downtown....It will be a while before I can hook up the 9 inch. I am young and want to be stupid and drive my car, turn some heads. I will never sell this car. I have been through so much to keep it. It is my first car. That in mind, I want to do the 9 inch right, just not right now.

I have sourced an 8.8 too. It is a 95 gt 5 lug disc setup. The posi has the extra friction plate, new axles, bearings, turned rotors, new pads, and 4.10 ford racing gears. I am really not crazy about the 4.10 rear end.

My friend just wrecked his 95 so I will be getting his 8.8 for $150.00

either way, i dont have the time at the moment, but here in about a month I will be taking some time off to give my car some attention. Maybe then, but maybe not.

Now it makes "cents" to me. Good luck with the swap.

BTW
I am sorta young (34) and definitely stupid, so I know where you are coming from.