🚗 Speedway Motors Ford 9″ Rear Axle Kit – 68-72 GM A-Body
🛠️ Upgrade Your GM A-Body with This High-Performance Rear Axle System
Transform your classic muscle car’s performance and reliability with the Speedway Motors Ford 9-inch rear axle conversion kit. Designed as a bolt-in upgrade, this kit replaces the factory GM rear end with Ford’s legendary 9-inch differential, offering enhanced strength, improved traction, and smoother gear engagement.
🔹 Why Choose the Ford 9-Inch for Your A-Body?
✔ Increased Strength – Nodular iron housing + reinforced ribbing for extreme durability.
✔ Customizable Gear Ratios – Accepts a wide range from 2.47:1 to 6.14:1 for street or track use.
✔ Service-Friendly Design – Drop-out third member makes maintenance & gear swaps easy.
✔ Disc Brake Kit Included – Big stopping power with vented 11-1/4″ rotors & GM metric calipers.
✔ Limited-Slip Posi-Traction Differential – Maximized traction & smooth performance.
🔹 Key Features & Benefits
✅ Direct Fit for 1968-72 GM A-Body Models – Bolt-in compatibility for easy installation.
✅ Pre-Assembled for Precision Performance – Proper backlash, preload, and pinion depth set.
✅ Fully Welded & Reinforced 3” Axle Tubes – Stronger than stock GM 10- or 12-bolt axles.
✅ 31-Spline Axles w/ Bearings & Studs Installed – High-strength construction for reliability.
✅ Upgraded Nodular Iron Center Section – 4 lbs of additional reinforcement for increased durability.
✅ Limited-Slip Clutch-Style Differential – Smooth operation, no clicking, & superior grip.
✅ Daytona Style Pinion Bearing Support – Maintains critical pinion depth under load.
✅ 11-1/4″ Rear Disc Brakes Included – Vented rotors, GM metric calipers, & brake pads.
✅ Precision Machined for Leak-Free Performance – No more messy oil leaks on your shop floor.
🔹 Technical Specifications
| Feature | Details |
|---|---|
| Brand | Speedway Motors |
| Position | Rear |
| Axle Splines | 31 |
| Axle Type | Semi-Floating |
| Brakes Included | Yes |
| Wheel Studs Included | Yes |
| Wheel Bolt Pattern | 5×4.75” |
| Housing Material | Nodular Iron |
| Axle Tube Outer Diameter | 3” |
| Gear Ratio | 3.50:1 |
| Differential Type | Limited Slip (Clutch-Type Posi) |
| Yoke U-Joint Series | 1310 |
| Rotors Included | Yes |
| Rotor Style | Plain Face |
| Hardware Included | Yes |
| Sold in Quantity | Kit |
🔹 What’s Included?
✔ (1) Ford 9” Nodular Iron Rearend Housing (Fully Assembled)
✔ (1) Complete Posi-Traction Limited-Slip Third Member (Pre-Built & Tuned)
✔ (2) 31-Spline High-Strength Axles (Bearings & Studs Installed)
✔ (1) 11-1/4″ Disc Brake Kit (Rotors, Calipers, Pads, & Brackets)
✔ (1) Pre-Set Daytona Pinion Bearing Support
✔ (1) Installation Kit (Hardware, Gaskets, Seals, & Fluids)
🔹 Ideal Applications
✔ 1968-72 GM A-Body Muscle Cars – Chevelle, GTO, Cutlass, Skylark & More.
✔ Restomods & Pro-Touring Builds – Increased strength for modern powertrains.
✔ Drag Racing & High-Performance Street Builds – Reliable & durable under extreme loads.
✔ Classic Muscle Car Restorations – Period-correct upgrade for long-term reliability.
❓ Frequently Asked Questions (FAQ)
🔹 How does this compare to a stock GM 10- or 12-bolt rear end?
- The Ford 9-inch is significantly stronger, with a larger pinion bearing, drop-out third member, and thicker axle tubes. It’s built for high horsepower applications.
🔹 What gear ratios are available?
- This kit comes pre-assembled with a 3.50:1 ratio, but the Ford 9-inch can accept ratios from 2.47:1 to 6.14:1.
🔹 Is this a direct bolt-in replacement?
- Yes! It fits factory GM 4-link suspension mounts with no modifications needed.
🔹 What type of brakes are included?
- The kit includes an 11-1/4” rear disc brake setup with GM metric calipers & vented rotors.
🔹 What type of differential is included?
- A clutch-style limited-slip (Posi-Traction) differential, ideal for street performance & mild track use.
🔹 Can I run aftermarket coilovers with this rear end?
- Yes! It’s compatible with most aftermarket coil-over suspension systems.
🚀 Order Now – Upgrade Your A-Body’s Performance with a Ford 9-Inch!
💪 More Strength, More Reliability, More Performance!
🛒 Limited Stock Available – Get Yours Today!
Third Member Install Kit
Make the installation of your new Posi-Traction Third Member a breeze! We’ve packed together some of the most commonly needed items to ease your installation with one click!
Kit Includes:
- Speedway 3rd Member Mounting Hardware for 8/9 Inch Rearends
- Used to attach the 3rd member (pumpkin) to the rearend housing
- Works with Ford 8″ and 9″ rear axles
- Includes aluminum washers
- Speedway 9 Inch Ford Rearend Axle Housing 3rd Member Pumpkin Gasket
- Reusable Differential Gasket
- Steel Core
- Universal Drive Shaft U-Bolts, 1-1/16 Inch Cap
- Speedway universal drive shaft U-bolts are forged steel for 50% more strength than standard units
- Fits U-joints with 1-1/16″ diameter caps
- U-bolt set – Speedway Ford 9 Inch Rearend 1310-Series Small Pinion Yoke
- From end of threads to inside of radius at deepest point is 1.708″ or 1-11/16″ plus
- Center to center of threaded ends is 1-3/8″
- Valvoline VV975 Synpower 75W90 Gear Oil, 3 Quarts
- Thermally stable, extreme-pressure gear lubricant
- Designed to operate in both high and low extreme-temperature conditions
- Recommended for limited-slip hypoid differentials and is compatible with conventional gear lubricants
- Maintains excellent low-temperature fluid protection
- Provides outstanding thermal stability for cleanliness and longer service life
- Contains special additives to assist in protecting gear teeth from rust and corrosion
- Contains special additives to reduce chattering in limited-slip differentials
- 3 quarts
- Red Line 80301 Limited-Slip Friction ModifierAdditive, 4 oz.
- Compatible with both petroleum and synthetic gear oils
- Reduces break-in temps as much as 50°F
- Add 1oz at a time to clutch-type limited slip or posi-traction units to eliminate chatter
- Exceeds API GL-5 specifications
- Engineered to provide the highest degree of protection and efficiency for better mileage, longer drain intervals, and less wear
- 4 ounce bottle
- Recommended Dosage:
- Use 4% for prevention of limited slip chatter in broken-in units (typical one 4 oz. bottle) or 4 to 8% for the break-in of new differentials.
- In non-limited-slip racing differentials and quick-change units using the Red Line ShockProof Gear Oils an additional 3 to 6% Red Line Limited-Slip Differential Friction-Modifier / Break-In Additive is recommended.
Brake Kit
- Disc Brake Stopping Power at a Great Value
This economical disc brake kit for Ford 9 inch and 8 Inch axles is simple to install and provides big stopping power, at a price nearly the same as replacing original drum brakes. That Ford rear end handles the power to make it go, but these binders clamp down when you say whoa! Today’s average family sedan can stop from 60 MPH in 120 feet, at nearly 1G of deceleration. You need the same stopping power. Your passengers, you and your car deserve the confidence of disc brakes and our kit delivers that confidence with exceptional value.
- Superior to Drum Brakes
Aftermarket disc brakes are superior to original drums in many ways: more braking force, less brake fade, and easier service. Stopping power starts with our newly manufactured GM Metric D154 style single piston calipers, commonly found on 1978-88 GM G-Body and A-Body cars. Large 11-1/4” diameter, 1” thick vented rotors provide more stopping leverage than common 9” or 10” drum brakes. Brake pads are easier to change than drum shoes, and our brake kit includes a street-friendly organic compound for long rotor/pad life. Replacement pads are common sized, available from your local auto parts store. Looking for more aggressive stopping power? We carry race-grade D154 disc brake pads that drop in just as easily.
- Fits Ford 9 Inch and 8 Inch Housings
This disc brake kit fits Ford 8 inch axles, as well as passenger car Ford 9 inch axle housings with “big bearing” ends (3.150” O.D. bearing, found on passenger cars from 1974-79). Included bracketry will adapt this kit to both “new style” and “old style” Ford 9 inch housing flanges with the 3/8” bearing retainer bolt holes. Bracket spacers are also included, allowing this kit to work with axle flange offsets of 2-3/8” or 2-1/2” common on Ford 9 inch passenger car rear ends. Axle flange offset is measured from the axle housing flange face (with bearing retainer removed) to the axle shaft flange face (side where the brake rotor/drum rides, including the thickness of the axle flange).
Guides & Documents
-
Differential Third Members Instruction Sheet (91049345)(PDF)
-
Differential Oil Additives Guide/Document (60780301)(PDF)
-
Disc Brake Pads Guide/Document (9193381)(JPG)
-
Brake Caliper Brackets Instruction Sheet (91031981)(PDF)
-
Brake Caliper Brackets Guide/Document (91031981)(JPG)
-
Differential Fluid Guide/Document (7958897851)(PDF)
Brake Pad Identification and Friction Surface Options Explained
Looking for some great street or racing brake pads for your muscle car, truck, or race car? You’ve come to the right place. From stock GM metric calipers used in plenty of disc brake conversions and in some classes of oval track racing to full on “big brake” packages, at some point in your vehicle’s life you’re going to need new pads. It doesn’t matter if you’re upgrading for a weekend track day or your race car’s pads are shot and need to be replaced before the next Saturday main event, we have what you need here at Speedway Motors.
If you’re trying to match up a new set of brake pads and you’re unsure which Wilwood caliper you have, the pad infographics shown below provide the dimensions of each pad, along with the caliper that it will fit. For OE-style calipers it helps to know the Friction Materials Standards Institute (FMSI) D-number. You can usually find this number somewhere on the pad backing plate or edge of the friction material. For example, GM’s extremely popular 1977-1988 “metric” calipers use a D154 pad. No matter the brand or friction material/compound, the D154 denotes the actual fitment to that caliper.
Wilwood Disc Brake Pad Offerings
- ProMatrix– Street performance/OEM replacement pad that is quiet-running with low dust, and low rotor abrasion. Fade resistant dual sport pad for street cars that autocross or do on-track events, as well as trucks that tow or have oversize wheels/tires. Popular for drag racing and off-road.
- PolyMatrix Q– Used with aluminum rotors in Sprint or Midget racing. Q pads are a ceramic formula to be quiet and low dust, with a smooth engagement.
- PolyMatrix E– Used with iron or steel rotors. Very consistent driver feel through entire operating range. Excellent street pad that can be used for track days and autocross, but also works well off-road and for drag racing.
- PolyMatrix B – Used with iron or steel rotors. Medium-high friction, good cold response. A race only pad popular for road courses, dirt and paved oval track, and off-road use, which works good at low temperatures but gets even more aggressive as it gets hot.
- PolyMatrix A– Used with iron or steel rotors. Very consistent driver feel through entire operating range. Wilwood’s most aggressive pad for road course, paved oval and dirt.
- SmartPad BP-10, BP-20, BP-30, BP-40 – These pads get increasingly aggressive as the numbers go up. BP-10 is usually what is included in Wilwood street brake kits. BP-20 is more aggressive. BP-30 and BP-40 are serious race pads, for professional road racing and asphalt oval track, and need to get hot before they really work well
Hawk Performance Disc Brake Pad Offerings
- HPS – Used on iron or steel rotors. High friction/torque hot or cold. Gentle on rotors, low noise. Much improved over stock braking.
- HP PLUS – Used on Iron or steel rotors. Extremely high friction. Works well for dirt and autocross. Elevated temperature resistance.
- BLACK – Used on iron or steel rotors. Excellent stopping power and good fade resistance at low to medium temperatures. Very rotor friendly with long pad life. Good dirt track or mild asphalt use.
AFCO Disc Brake Pad Offerings
- SR32 – Developed for the right fronts of dirt cars where low grip is needed to help build bias in the front brake system and help the car turn better when you have to use 4 wheel brakes.
- C1 – Designed for medium to low brake temperatures and provides good cold bite while being rotor friendly. The pad is best used on IMCA style modifieds, the fronts of “Outlaw” style modifieds, drag racing, and most street applications.
- SR33 – Developed for improved stopping power over the standard C1 compound and has a wider temperature range that will reduce brake fade. The compound is made for the front and rear of dirt cars and rear asphalt cars where a medium grip pad is needed.
- C2 – Designed for a wide range brake temperatures and provides excellent cold bite and aggressive braking power. The pad is best used on rear of IMCA style modifieds, the rears of “Outlaw” style modifieds, fronts of asphalt cars, and outlaw drag racing.
- SR34 – Developed for improved stopping power over the standard C2 compound for rear dirt cars and front asphalt cars. The higher temperature range (200-1,600 degrees) makes this pad very versatile and resistant to fade while at the same time giving you a heavy grip pad with reduced rotor wear.
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