Replace or inspect the torque-axis (upper) engine mount on a 1966 Chevrolet Corvette with 327ci V8 engine, which controls engine torque rotation and stabilizes the powerplant under load.

Warnings

Tools required

Parts

• Torque axis engine mount assembly × 1 — Use OEM specification or equivalent
• Engine mount through-bolts × 2 — Use OEM specification (if corroded)

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Allow engine to cool completely if recently operated
3. Disconnect negative battery cable to prevent accidental starter engagement
4. Raise front of vehicle and support securely on jack stands under frame rails
5. Apply penetrating oil to all mount fasteners and allow to soak for 15-20 minutes if fasteners show corrosion

Procedure

1. 1

   Locate torque-axis engine mount
   From underneath the vehicle, identify the engine mounts. The 1966 Corvette 327 uses two side-mounted engine mounts (left and right) that bolt the engine block to the frame mount brackets, plus a separate rear transmission mount. Each side mount consists of a rubber isolator sandwiched between a block-side bracket and the frame bracket, secured by a through-bolt.
2. 2

   Install engine support
   Position an engine support bar across the inner fenders or engine compartment, securing it to the fender lips or shock towers. Attach a chain or adjustable support hook to a secure engine lifting point (such as the intake manifold carburetor stud or a dedicated lifting bracket). Alternatively, position a floor jack with a wood block under the oil pan to support engine weight. Apply just enough upward pressure to take weight off the mount, but do not lift the engine yet.
3. 3

   Remove frame-side mount bolt
   Locate the through-bolt securing the mount bracket to the front frame crossmember or radiator support. Verify the bolt and head size before selecting tools; the 1966 Corvette engine mount through-bolts are commonly 7/16" diameter (5/8" hex head). Using appropriate wrenches, hold the nut on one side while loosening the bolt from the other. Remove the bolt, nut, and any washers completely. Note the orientation and position of washers for reinstallation.
4. 4

   Remove engine-side mount bolt
   Locate the through-bolt securing the mount bracket to the engine block side mount bracket (the bracket bolts to the side of the cylinder block, not to the intake manifold). Using appropriate wrenches, hold the nut while loosening the bolt. Remove the bolt, nut, and any washers completely. Keep all hardware organized for reinstallation.
5. 5

   Lift engine slightly
   Using the engine support bar or floor jack, carefully raise the engine approximately 1-2 inches to create clearance between the mount components. Raise slowly and watch for interference with hood, air cleaner, or other components. Stop lifting once the mount is unloaded and has visible clearance.
6. 6

   Remove torque-axis mount assembly
   With the engine raised and mount unloaded, remove the complete torque-axis mount assembly from the vehicle. It may require slight maneuvering or rotation to clear surrounding components. Inspect the removed mount for cracking, tearing, or separation of rubber from metal components.
7. 7

   Clean mounting surfaces
   Using a wire brush, clean the mounting surfaces on both the engine block mount bracket and the frame side mount bracket. Remove all dirt, rust, and old rubber residue. This ensures proper seating of the new mount and accurate torque readings during installation.
8. 8

   Position new torque-axis mount
   Position the new torque-axis mount assembly between the engine and frame mounting points. Ensure the mount is oriented correctly with the rubber isolator positioned to absorb torque rotation (consult mount markings or packaging for proper orientation). The mount should align freely with both mounting bolt holes.
9. 9

   Install engine-side through-bolt
   Insert the through-bolt through the engine mounting tab and mount bracket, ensuring any washers are positioned as they were during removal. Thread the nut onto the bolt by hand. Do not tighten at this time—leave the bolt snug only to allow for alignment.
10. 10

    Install frame-side through-bolt
    Insert the through-bolt through the frame crossmember mounting point and mount bracket, with washers in their original positions. Thread the nut onto the bolt by hand. Leave snug only—do not fully tighten.
11. 11

    Lower engine onto mount
    Carefully lower the engine using the support bar or floor jack, allowing the engine weight to settle onto the new torque-axis mount. Lower slowly until the mount is fully compressed under normal engine weight and no load remains on the support equipment. Verify that the mount is seated properly and both bolts align without binding.
12. 12

    Torque mount fasteners
    With engine weight fully on the mount, torque the through-bolts per factory specification. CONFIRM the value against the 1966 Corvette Chassis Service Manual before final tightening; do not rely on the conservative 50 ft-lb estimate without verification. Torque the engine-side bolt first, then the frame-side bolt. Verify both nuts are secure and bolts do not rotate during torquing.
13. 13

    Remove engine support
    Remove the engine support bar, chain, or floor jack from under the vehicle. Verify the engine sits level and the mount shows no signs of misalignment or excessive deflection. Rock the engine gently by hand to confirm the mount is functioning and properly seated.

Reassembly

1. Reconnect negative battery cable
2. Remove jack stands and lower vehicle to ground
3. Start engine and observe mount operation—there should be minimal engine movement and no clunking or banging noises during acceleration or deceleration
4. Test drive vehicle and verify smooth operation without excessive vibration or engine movement under throttle application

Verification

• Engine sits level and stable with no visible sagging or misalignment
• No excessive engine movement when revving engine in neutral (mount should absorb torque rotation without metal-to-metal contact)
• No clunking, banging, or knocking sounds during acceleration or deceleration
• Both mount through-bolts are tight and show no signs of loosening
• No unusual vibration transmitted to the chassis or steering wheel during idle or driving

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