This procedure covers the replacement of the front engine mounts on a 1966 Chevrolet Corvette with 327ci V8 engine, including disconnection, removal, installation, and torquing to specification.

Warnings

Tools required

Parts

• Front engine mount (driver side) × 1 — Use OEM specification
• Front engine mount (passenger side) × 1 — Use OEM specification

Preparation

1. Park vehicle on level, solid surface and apply parking brake.
2. Allow engine to cool completely if recently operated.
3. Disconnect negative battery cable to prevent electrical shorts.
4. Raise front of vehicle and support securely on jack stands under frame rails.
5. Inspect engine mounts visually for damage, cracks, or separation before beginning removal.
6. Apply penetrating oil to all mount fasteners and allow to soak for 15 minutes if fasteners show corrosion.

Procedure

1. 1

   Position engine support jack
   Place a floor jack with a wood block (minimum 2x6 inch lumber) under the engine oil pan. Position the wood block to distribute load across the pan width, not at the sump drain plug. Raise jack until it just contacts the oil pan with slight upward pressure, but do not lift the engine yet.
   ⚠Use adequate wood blocking to prevent damage to oil pan. Never jack directly against the oil pan drain plug or sump.
2. 2

   Remove driver side mount through-bolt
   Locate the through-bolt that passes horizontally through the engine mount bracket and frame mount. This bolt secures the engine-side bracket to the frame-side mount. Remove the nut from the through-bolt, then drive or pull the through-bolt out of the mount assembly. The bolt may require light tapping with a hammer to break free.
3. 3

   Remove driver side engine mount-to-block bolts
   Remove the 2 bolts that secure the engine mount bracket to the engine block. These bolts thread into the engine block casting. Support the mount assembly as you remove the final bolt to prevent it from falling.
4. 4

   Remove driver side engine mount-to-frame bolts
   Remove the 2 bolts that secure the frame-side mount to the front crossmember. With all fasteners removed, lower the mount assembly from the vehicle. Note the orientation and any shims present for reinstallation.
5. 5

   Remove passenger side mount through-bolt
   Repeat the through-bolt removal process on the passenger side. Remove the nut and extract the through-bolt that passes through the engine mount bracket and frame mount.
6. 6

   Remove passenger side engine mount-to-block bolts
   Remove the 2 bolts securing the passenger side engine mount bracket to the engine block. Support the mount as the final bolt is removed.
7. 7

   Remove passenger side engine mount-to-frame bolts
   Remove the 2 bolts securing the frame-side mount to the crossmember on the passenger side. Remove the mount assembly and note orientation and any shims.
8. 8

   Clean mounting surfaces
   With both mounts removed, use a wire brush to clean all mounting surfaces on the engine block and frame crossmember. Remove rust, old gasket material, and debris. Inspect the engine block mounting bosses and frame brackets for cracks or damage.
9. 9

   Install driver side mount to frame
   Position the new driver side mount to the frame crossmember, ensuring proper orientation with the mount rubber facing upward. Install the 2 frame mounting bolts finger-tight. Do not torque at this stage.
10. 10

    Install driver side mount to engine block
    Raise the floor jack slightly to lift the engine enough to align the mount bracket with the engine block mounting holes. Install the 3 engine mount-to-block bolts finger-tight. Verify alignment before proceeding.
11. 11

    Install driver side through-bolt
    Insert the through-bolt through the engine bracket and frame mount. Install the nut finger-tight. Ensure the mount rubber is properly seated and not twisted.
12. 12

    Install passenger side mount to frame
    Position the new passenger side mount to the frame crossmember with correct orientation. Install the 2 frame mounting bolts finger-tight.
13. 13

    Install passenger side mount to engine block
    Adjust engine position using the floor jack to align the passenger side mount bracket with engine block holes. Install the 3 engine mount-to-block bolts finger-tight.
14. 14

    Install passenger side through-bolt
    Insert the through-bolt through the passenger side engine bracket and frame mount. Install the nut finger-tight. Verify mount rubber is properly seated.
15. 15

    Torque all fasteners to specification
    With all mounts installed and engine weight settled naturally on the mounts, torque all fasteners per the factory service manual specifications. Verify against the 1966 Corvette shop manual: engine mount-to-block bolts (approximately 30-35 lb-ft), engine mount-to-frame bolts (approximately 50 lb-ft), and through-bolt (approximately 50 lb-ft).
    ℹ️Lower jack slightly to allow engine weight to settle onto mounts before final torquing. This ensures proper load distribution.
    Torque spec

    Engine Mount-to-Block Bolts65 Nm (48 lb-ft)

    Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)

    Through-Bolt85 Nm (63 lb-ft)
16. 16

    Remove engine support and lower vehicle
    Carefully lower and remove the floor jack from under the engine oil pan. Lower the vehicle from jack stands and remove stands from under the frame.
17. 17

    Reconnect battery and perform final inspection
    Reconnect the negative battery cable. Visually inspect both engine mounts to ensure all fasteners are installed and properly torqued. Check for proper clearance around mounts.

Reassembly

1. Ensure all fasteners are torqued to specification in the correct sequence as detailed in step 15.
2. Verify engine sits level and centered in the engine bay with no visible misalignment.
3. Confirm no interference exists between engine accessories and frame or body components.

Verification

• Start engine and observe for excessive vibration or movement. Engine should idle smoothly without shaking.
• With engine running, have an assistant apply load by selecting drive (automatic) or releasing clutch slightly (manual) while observing mounts for excessive deflection or separation.
• Visually inspect all mount fasteners after test to ensure none have loosened.
• Road test vehicle and verify no unusual vibrations at idle or during acceleration.
• Re-inspect torque on all fasteners after 50-100 miles of driving.

More procedures for this vehicle