General Motors OEM Muscle Car Rear End For GM A-body Cars, 12 Bolt Posi-traction For Sale
General Motors OEM Muscle Car Rear End For GM A-body Cars, 12 Bolt Posi-traction
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This was a “spare” racing rear end purchased and rebuilt in the late 1990’s with a 4.56:1 ratio which was only used a few times before the unit was removed and stored and the car changed back to a driver. It has been stored inside since then and is in “like new” condition, even the brake pads look new.This will need to be shipped by a freight carrier, based on a conversation with a broker I have estimated it at 250, if it’s less I will charge actual cost, if it’s more, I will eat it.The rest of this description is from AI:The number you gave — 396927NF — looks like a GM rear axle tube stamping, not a full serial/VIN. GM (especially under General Motors) used these codes in the late 1960s–early 1970s to identify axle assemblies.
🔎 What “396927NF” likely means
396927 → Casting/part number tied to a 12-bolt rear end housing used around 1969–1970
NF → Axle code suffix
Most commonly decoded as:
3.31 gear ratio
Often Positraction (limited-slip)
Built for performance A-body cars
🚗 Typical applications (fitment)
This type of rear end is most commonly found in GM A-body cars:
Chevrolet Chevelle (SS and performance trims)
Chevrolet Malibu
Pontiac GTO
Oldsmobile Cutlass
Buick Skylark
👉 Direct bolt-in fit:
1968–1972 GM A-body cars
⚠️ Notes:
Exact fit depends on control arm mounts, spring perches, and width
Chevy 12-bolt rears differ slightly from BOP (Buick/Olds/Pontiac) units
⚙️ Specs (typical for this setup)
12-bolt differential
8.875" ring gear
3.31:1 ratio
Likely Positraction
Drum brake setup (factory)
💰 Value (excellent condition)
As of current collector market trends:
Bare housing: $800 – $1,500
Complete, rebuilt (posi, gears, brakes):
👉 $2,000 – $3,500+
Higher if:
Date codes match a numbers-correct SS car
Professionally rebuilt with documentation
⚖️ Weight (complete assembly)
Approximate shipping weight with:
gears
axles
drum brakes
backing plates
brake lines
👉 200 – 250 lbs total
Breakdown:Housing + center: ~150–180 lbs
Axles + brakes + hardware: ~50–70 lbs
📦 Shipping considerations
Typically shipped via freight (not standard parcel)
Needs palletizing
Common freight class: ~150–200
Expect shipping cost: $150–400 (domestic U.S.) depending on distance
