Ford 8 inch rearend swap

[RustyRatRod]

Good idea. I'm thinking it was a Mustang because the guy I got it from was a mustang guy and he got it when he bought some other guys pile of mustang parts. I'll look tonight. These things are inexpensive. I've seen them as low as $125 or as high as $300. But this is the only one I've found with 1:3.00 gearing.

Actually, that's 3.00:1. The drive shaft (pinion gear) number comes first. The "1" refers to the axle turning over one time. SO, that means drive shaft turns 3 times, rear axle turn once, so it's a 3:1 ratio. Decent gear for cruising. Ford did that a lot. 3:1, 4:1, and 5:1. Most Ford guys say "300 gear", "400 gear" and so on. Most other makes went 3.23, 4.10 but Ford rounded some of their gears off even like that.

 

[Unconventional]

That's the idea. I cannot be sure what car it came out of, but the guy listed it as 1964.5 v8... but he got it from a guy, who got it from a guy, etc. It's got 1:3.00 gearing and I think my valiant has 1:2.93(?) or something very close.

According to my notes, '65-66 Mustangs were 57 1/8" wide drum face to drum face for the 8" and the 9". Mavericks and Comets were at 56 1/2".

 

[CudaJason]

I have a Ford 8 inch, that is going to go into one of my cars. Have not started installing, yet. But by measurements, and talking to others who have done this swap, it is "almost" a bolt in if you use the correct 8 inch rear. Needs to be from a early V-8 Mustang, Comet, (and I think) Granada. It looks like the only "mod" is the U-joint. Most use a combination of a conversion joint, and a stock joint. I will be modifying the my driveshaft for a stock Ford U-joint. I got my rear housing from a junk yard with a section of driveshaft still attached.
One thing to watch for the 8 inch must be from a V-8, to get the 5 on 4 1/2 bolt pattern. The 6 cyl Fords got a 4 bolt pattern.
I got lucky on mine. Found the pumpkin at a swap meet. Had 4.30 gears and a spool for $200.00 Two days later went to the junk yard for something, and saw the drum to drum housing laying on the ground, just inside the gate. Got it for $100.00

I'm getting ready to wrap up my 66 Barracuda getting back on the road and i have swapped in an 8 inch rear from a 64 mustang. I have done research on the u joint to convert and i think a Spicer 5788 should do it. Do you know what joint you used to convert your driveshaft to the 8 inch yoke?

 

[CudaJason]

bump

 

[middleagecrisis]

Are you guys talking about the light duty Ford 8" rearend of old or the Ford 8.8" found in the later model Mustangs and Explorers? The 8.8 is plenty strong and can be found with Trac-Loc and good gear choices from the factory, plus disc brakes. I've abused plenty of them in the Fox Body Mustangs and they've got plenty of aftermarket support. Going to a light duty Ford 8" seems like a huge step backwards to me. You could probably find a 8.25 for next to nothing if you looked around and it would be stronger than the 8". I sold one out of my Duster for $125 when I swapped in the 8.750 currently in the car.

 

[Charrlie_S]

I'm getting ready to wrap up my 66 Barracuda getting back on the road and i have swapped in an 8 inch rear from a 64 mustang. I have done research on the u joint to convert and i think a Spicer 5788 should do it. Do you know what joint you used to convert your driveshaft to the 8 inch yoke?

I am having my Valiant drive shaft modified to use the Ford U-joint. Using the "ears" from a ford drive shaft. That way don't have "oddball" parts.

 

[CudaJason]

Are you guys talking about the light duty Ford 8" rearend of old or the Ford 8.8" found in the later model Mustangs and Explorers? The 8.8 is plenty strong and can be found with Trac-Loc and good gear choices from the factory, plus disc brakes. I've abused plenty of them in the Fox Body Mustangs and they've got plenty of aftermarket support. Going to a light duty Ford 8" seems like a huge step backwards to me. You could probably find a 8.25 for next to nothing if you looked around and it would be stronger than the 8". I sold one out of my Duster for $125 when I swapped in the 8.750 currently in the car.

Yes the early 8 inch ford. I had one already, and it was dimensionally a match to the 7 1/4 inch rear that was in my 66 barracuda. Absolutely the 8.8 much stronger, but I don’t need a rear that will hold up to 500 horsepower as this is a driver, with a basically stock 5.9 magnum motor I just swapped in it. Plus like I said I had it, and it already had a 3.25 gear and a trac loc in it.

 

[CudaJason]

Most people don’t want an 8 inch ford, but if you are cool with having rear drum brakes, and don’t need a rear that will hold up to a 500 horse motor an 8 inch is just fine for your 350 to 400 horse small block. I’ve used them in tns of cars and normally they are dirt cheap.

The cool thing about using one in an early A body, is that if you get the right one it is a direct swap with 7 1/4 rear with only a conversion u joint needed. No welding, no narrowing and you can even use the 7 1/4 inch u bolt spring plates, and swap the parking brake cables out of the 7 1/4 into the 8 inch. A 8 inch ford from a 63 to 65 fairlane or comet or from a 64 to 68 mustang will work great. Just make sure it has 5 lug axles some did have 4 lug axles.

All you really need to complete the swap is the conversion u joint at the rear axle to swap into you original 7 1/4 inch rear drive shaft. A Spicer 5788X u joint will convert from the 7260 series mopar yoke on the driveshaft to the 1310 series yoke on the 8 inch ford axle. I just finished this up in my 66 barracuda and it works perfectly.

Ford on the left and mopar on the right. I did replace the spring perch brackets in the ford rear just because I hated the way they looked but they would have worked fine.

Here it is installed on a new set of super stock springs

Instant 4.5 inch bolt pattern upgrade.

Plus you get 10 inch brakes, and you can use the 2.25 inch wide shoes by buying the 2.25 inch drums when re building the brakes. The entire rear brake overhaul cost about 90 bucks with all new hardware drums and wheel cylinders from Raysbestos when bought from rock auto. Factor mopar 7 1/4 inch parking brake cables will pop right into the ford backing plates.

Works pretty well.