rear end swap question

evren · 06-19-2006

i have a 66 200ci mustang coupe. it's got the 7 1/4 (or whatever) rear end that seems to be making some noise. i'm going to drop a V8 in the car eventually so i got an 8inch rear from another 60's mustang. If i swap the 8" rear in, does anything else need to change? Drive shaft length? U-joints on the driveshaft-to-rear connection? rear leaf springs? e-brake stuff?

thanks.

edgars23 · 06-20-2006

As long as the 8" rear end that you picked up is from a 64-66 mustang, you should be able to just drop it into place. If you bought a 8" rear from a 67-73, the actual spacing of the mounts will be different from the 64-66 model and you will have to have them adjusted and then the rear end re-straightened. The legnth may also vary on the housings, but I am not 100% sure about this.
Your leaf springs and e-brake should stay the same. Rear suspension is pretty much the same on v6 & v8 models. Your front suspension is what will need to be upgraded to handle the added weight of the v8 engine. If you haven't done it already, I would still recommend replacing/freshening up your rear end when you do the swap. All your bushings and shocks (and maybe even the leaf springs) should be changed if they look like they are in bad shape. Since you will be disassembling it to get the rear end out, it would make life easier for you to do all the work you need to do to the rear at once.
Good luck on the swap and have fun.

evren · 06-20-2006

thanks

i already rebuilt the whole back suspension earlier. back then i did not think i was going to put an V8 in the car. so that's all set. new bushings, shocks and leaf springs. all set.

are the U-joints the same too?

edgars23 · 06-20-2006

I'm not sure about the drive shaft legnth or the U-Joints. If you are lucky, you will be able to reuse them. Hopefully someone can you knows for sure can chime in for you. I will look into it if I have time.

69stangman · 07-05-2006

The same U-joints are used in the rear for a 65-67 200 or 289. I believe the 68 is different for the 289 and 200 manual, but the same for 200 automatic. In the front, the 65-67 joints are the same for the 289 and 200, but I don't know about other years or displacements. It really depends on the year, engine, and tranny that the rear end came from.

lads_john · 07-05-2006

Quote:

Originally Posted by evren

thanks

i already rebuilt the whole back suspension earlier. back then i did not think i was going to put an V8 in the car. so that's all set. new bushings, shocks and leaf springs. all set.

are the U-joints the same too?

They're only about $10 at NAPA. Stick some new
ones in there while you're at it.

Cracker289 · 08-07-2006

I just put a 9 inch rear from a 7 Fairlane in my 66 Coupe. The axle tube is fatter, so I need different U-bolts and shock mounting plates. Does anyone know if the 7 nine inch rear is the same width axle tubes as the 67-73 Mustangs? If so I'll just buy u-bolt and shock plates for a 67, but I am not too sure what I need...

mot250 · 08-08-2006

The axle widths got bigger after 66, hence swapping a 66 axle into a later car essentially gives you a cheap narrowed rear. I think the perches were the same distance on quite a few of the years making the swap easier.

Axle tube diameter should be the same for the 7 1/4 and the 8 and early 9 inch rears.

I swapped a 9 inch from a mid 80's Granada into my 66. Same overall length and perch distance as 66 but with the big tubes so I slotted the u-bolt holes in the mounting plates or you could buy new plates to fit the bigger tubes (I was on a "just-married" budget when I did the swap). I also upgraded to bigger 76 Ranchero GT 2.5 X 11 inch drums on the rear so I had to modify the Ranchero backing plates to fit the Granada rear but the stock Mustang parking brake cable fit together like a charm.

Side note on the V-8 swap in the front. It will fit and work with the I-6 steering and suspension but the steering linkage will hit the starter in sharp turns.

Cracker289 · 08-09-2006

Quote:

Originally Posted by Cracker289

I just put a 9 inch rear from a 7 Fairlane in my 66 Coupe. The axle tube is fatter, so I need different U-bolts and shock mounting plates. Does anyone know if the 7 nine inch rear is the same width axle tubes as the 67-73 Mustangs? If so I'll just buy u-bolt and shock plates for a 67, but I am not too sure what I need...

What I was TRYING to say, was that I put a 9 inch rear from a 57 Fairlane into my 66. The 57-59 full size Fords have a 9 inch rear that has the same axle to axle width as the 65-66 Mustang, and the spring perches are the same. It's a direct bolt in. My problem is the 57 Fairlane axle tube is about 3 inches, whereas the 66 Mustang rear has a skinny axle tube, I think it's 2 1/2. In my Mustang catalog, it says the 67-73 axle is 3 3/8. So it would appear to be fatter than the 57 nine inch. Not too sure what I'm going to do. I think I will try to find someone with 67 spring / shock mount perches and put those on, should still hold the rear end in place.

The reason this did not come out earlier, I posted it from home, and the "5" key doesn't work all the time. So I'm thinking I am writing "57" and not checking, but only the 7 is showing up. I didn't even check, just clicked "submit"!

Twister · 08-09-2006

IF the car is an auto, than it has the same driveshaft, yoke and all as a V8. the 67-68 8 inch is a little eider. I would stay away from a 9 inch due to the weight and the ammount of power that they rob. your 200 would be a dog with one