Ford Mustang Forum banner

Status
Not open for further replies.
1 - 20 of 20 Posts

·
Registered
Joined
·
49 Posts
Discussion Starter · #1 ·
i have a 200ci 1966 mustang with a 7.25 inch rear end. i want to p8ut a 302 in it. the rear end seems to be making noise. so i want to replace it. since i'm eventually going to a 302 i want to put an 8inch or 9 inch.

there's a 1970 9inch with disc brakes from a mustang available that i want to buy.

will this rear end swap right into a 1966 mustang?
will i have to change the drive shaft for this swap?
will the disk brakes cause any problems. ( i have druma ll around now but i will put a stainless steel front disk kit in with this swap)?

anthing else i need to know?

thanks a lot!

-evren
 

·
Registered
Joined
·
360 Posts
The 1970 rear axle is wider than the '66, so it would need to be shortened to proper width. The 8 or 9 inch will be strong enough unless you intend to race or run DOT slicks. The only 9" rears that bolt in are from '65/'66 Mustangs or the '57-'59 Ford full size cars. All of the later years Mustang rears are 2" wider.
 
G

·
Yeah, Putt is right.

But where are you located and how much are they asking for that 1970 9"? It would fit nicely in my 67 and I've been lookin all over hell's creation to find a 9" for my car.
 

·
Registered
Joined
·
11 Posts
I have a 66 mustang with a 302 and c4. I pulled an 8in rearend out of a 77? granada along with the front spindles. The rear end will drop straight in without any other modifications they also have 10in drums and if your lucky you can find an 8in rear end with a locker. But most 8in out of granada's have a pathetic rear gear, mine is a 2.79. Also if you havent heard about it you can use the granda front disc's to convert your front drums to discs.

Another thing is i forget what company but one of the rearend companies is starting to produce alot of aftermarket parts to beef up the 8in rearend. I have also heard that the 8.8" rearend fits and is almost as strong as a 9in
 

·
Registered
Joined
·
360 Posts
I think it might be Currie Enterprises in So Cal that is making the 8" upgrade pieces. I don't have any handy info on the 8.8" fit, the only thing I do not like about the 8.8" is the c-clip style axle retention system.
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #9 ·
mustang and fords magazine has a diff. upgrade article in which they say that you can drop 8.8inch rear ends into classic mustangs. they say to contact drivetrain depot and they will ship out an 8.8inch and you can drop it in. i emailed drivetrain deopt and they told me that they do not recommend 8.8s in classic mustangs because the drive shaft is at a bad angle. so it appears to not be a simple swap i guess.
 

·
Registered
Joined
·
682 Posts
That bit about 8.8s and bad driveline angle is pure sh!t. The only 8.8s that will drop right in a 65-66 are custom built and you could correct any driveline angle problems in the process of building it. Driveline angle is more dependent on transmission position anyway, even though the rear end plays a role. Hell, the only way I've ever seen people deal with rear-end related driveline angle issues is to silde in some shims. Besides, you'll be welding on spring perches to an 8.8 anyway, so the drivline angle IS UP TO YOU!

Rear discs werent a stock item...that alone is worth $200...grab it! If it's actually a Versailles rear, it'll fit a 66 a hell of a lot better than a 70, so there you go. If the discs are just bolted on to a normal 9", bolt them on a correct 9" or maybe an 8", depending on the kit, most do both rears, and sell the 1970 rear; you could get $200 out of it, no problem.
HTH
 
G

·
8.8's aren't nearly as strong as a 9", I wouldn't advise even entertaining that idea. Maybe for your application it would work, but if in the future you really wanted tp pump some steroids into that motor, you'd blow that 8.8 apart.

Also, depending on how much they're asking for that 9" out of that 1970, it may be worth your while to buy it and sell it off for more. Like someone said, it wasn't factory to have rear disks, so it's worth mucho dollars.
 

·
Registered
Joined
·
114 Posts
You can put it in, but there are more than a few considerations.
It is too wide. But you can work around that with custom offset wheels if you have to. Better to have the rear end narrowed professionally though.
The brake hose you'll have to figure out. I know your existing one won't work, but what will I don't know offhand. Likely someone else will though.
You'll need u-bolts and spring plates to fit the larger diameter 9 inch's axle tubes.
And you will need a driveshaft about 2 inches shorter. And your existing driveshaft rear yoke won't bolt to the 9's yoke anyway.
My primary concern would be these "disk brakes". Not stock so they must have been added. I'd very much want to know what they were before I even considered the rear. Years ago the hot ticket was to swap in a Lincoln Versailles disk rear. Now very passe as the brakes weren't actually all that great. The rotors are rather prone to cracking and the prices for OEM replacement parts rival that of nice high performance stuff. Another old school possibilty was a a set of aftermarket Wilwoods. Good brakes but very many of them were intended for race cars and had no provision for a parking brake. This didn't stop people from using them anyway, I kicked the idea around myself a time or two.
I'd beware of setups like these. You can adapt non-vented disks from a Crown Victoria fairly cheaply these days. For a bit more and junkyard scrounging you could add vented Lincoln LSC disk brakes to an 8 inch or a 9 inch rear end. And of course all the more expensive aftermarket stuff.
Just because it's a 9 and just because it has disks doesn't mean this particular rear is all that great or even anything you'd really want. It might possibly be something really good though, shop carefully and good luck.
 

·
Registered
Joined
·
11 Posts
not to get too far off subject but GypsyR is there a website or anywhere that I can go that has information on swapping in Crown Vic or Lincoln LSC rear discs to an 8in rear? I have an 8in and would definitily be interested in rear discs.
 

·
Registered
Joined
·
103 Posts
Are you sure it's a 1970 axle? If it is, it may be a bolt in deal.

I put a 1968 9" in my '66 and it bolted right in. Driveshaft an all. Everyone said I would have to shorten my driveshaft but it fit fine and even accepted the original rear u-joint.

The 65-66 axles are narrower than the later years but that doesn't necessarily mean you have have to narrow the '70 axle. Measure the '70s axle width end to end vs the '66. The '68 axle I put in my '66 was 1" wider on each side than the orginal '66 axle. Actually made the stock ralley wheels look better sitting in the wheel well! So I'd actually recommend the wider axle myself. Measure the centerline of the axle to the centerline of the u-joint pocket, that'll let you know if you'll need a different length driveshaft.

The disc setup on a '70 axle is probably some sort of conversion so it may be a challenge figuring out what's actually on it. Rear discs will require an adjustable brake proportioning valve and a creative emergency brake hookup.

Grab a tape measure and start measuring!
 

·
Registered
Joined
·
1 Posts
awww man i wish i knew at least some stuff about cars. i dont even know what to do w/ my car 1966 coupe stock 200 ci auto and was hoping of putting a 373 standard and yeah i guessing from what i been hearing everything gona have to come off rear end n breakz and i dont know what else. well i know im not going to be doing all this to my car ima take it to a mechanic and they should know whats right and whats not what fits and what dosn't. all i been doing lately is trying to do reshearch on what i want/ im sure about the 302/373 engine for this year and e2 body for next i just dont know the steps in between omg i gtg sleep ill post mroe ;-)
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #16 ·
are 67-70 8 inch rears alsoo too wide to drop right into a 66 mustang? is shortening them pretty cheap or is it cheaper to find one the right size
 

·
Registered
Joined
·
433 Posts
They are an inch or two wider. They will fit but you will need to get offset wheels for everything to look right. Narrowing a rear end is costly. Go get the proper rear end. There are still plenty of 8 inch rearends out there and the car will be right when you are done.
 
G

·
I'm not even sure if it will fit because I don't know if the spring perches are in the same spot.

Also, yes, they're exactly 2" wider. 71-13's are exactly 2 more inches wider.
 

·
Registered
Joined
·
433 Posts
To fit correctly the rearend is going to have to come out of a 65-66 'stang or a 57-59 full size ford...I've been told that rearends from under Granadas fit but I'm not sure on that one maybe someone else may know.
 

·
Registered
Joined
·
49 Posts
Discussion Starter · #20 ·
thanks a bunch for the advice. i found a 65/66 8inch from a mustang on craigslist. $200 - perfect!

can't wait to get it installed.
 
1 - 20 of 20 Posts
Status
Not open for further replies.
Top