Drivetrain› Differentials and Rear-End Components

QA1 Precision Products, Inc

QA1 67-70 Ford Mustang 9in Standard Rear Axle Assembly

$3,348.46

SKU: Q00B R904S

Special Order
Special Order
Ships in 4–6 weeks
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Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

The QA1 R904S is a fabricated 9-inch rear housing designed for 1967-1970 Ford Mustangs already equipped with a QA1 4-link suspension system. This housing offers improved strength, precise suspension geometry, and simplified serviceability for high-horsepower street and strip builds.

It features a fabricated steel center section for maximum rigidity and fully formed trailing arm brackets to reduce flex. Heavy-duty 3-inch OD, 1/4-inch wall axle tubes ensure durability in high-performance applications.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandQA1 Precision Products, Inc
Part NumberQ00B R904S

Videos

QA1’s Bolt-In 9 Inch Rearend Upgrade

QA1’s Bolt-In 9 Inch Rearend Upgrade
QA1 4-Link Rear End Install on a Classic Muscle Car Part 1 | EP 26 RUSTORATIONS 1972 Nova

QA1 4-Link Rear End Install on a Classic Muscle Car Part 1 | EP 26 RUSTORATIONS 1972 Nova

Buy with Confidence

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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