Replace a single worn or broken valve spring on the 390ci V8 engine by removing the affected cylinder head and using specialized valve spring compressor tooling.

Warnings

Tools required

Parts

• Valve spring (390ci V8) × 1 — Use OEM specification
• Valve spring retainer/keeper set × 1 — Use OEM specification
• Cylinder head gasket × 1 — Use OEM specification for 390ci V8
• Intake manifold gasket set × 1 — Use OEM specification
• Exhaust manifold gasket (driver or passenger side as applicable) × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Head bolt sealer or thread sealant × 1 — Use OEM specification

Fluids

• Engine oil with appropriate viscosity for 390ci V8 — 5 qt
• Engine coolant (ethylene glycol based) — 4 qt

Preparation

1. Disconnect negative battery cable
2. Drain engine coolant into suitable container by opening radiator petcock and removing lower radiator hose
3. Drain engine oil into drain pan
4. Remove air cleaner assembly
5. Identify which cylinder has the failed valve spring and determine if driver or passenger side head removal is required
6. Label and disconnect all vacuum lines, electrical connectors, and hoses connected to cylinder head being removed
7. Remove spark plug wires and spark plugs from affected cylinder head

Procedure

1. 1

   Remove valve cover
   Remove valve cover bolts and lift valve cover from cylinder head. Clean all gasket material from valve cover and cylinder head mating surfaces using gasket scraper. Inspect valve train for obvious damage or wear.
2. 2

   Remove intake manifold
   Disconnect throttle linkage and fuel line from carburetor. Remove carburetor from intake manifold. Remove intake manifold mounting bolts in reverse order of tightening sequence (work from center outward). Carefully lift intake manifold away from engine and set aside. Keep all bolts organized.
3. 3

   Remove exhaust manifold
   Disconnect exhaust pipe from manifold at the flange. Remove exhaust manifold bolts and carefully remove manifold from cylinder head. Inspect manifold studs for damage.
4. 4

   Remove rocker arm assembly
   Loosen rocker arm shaft mounting bolts evenly in multiple passes to prevent warping. Remove rocker arm shaft assembly as a complete unit. Keep pushrods in order by placing them in a numbered rack or cardboard template showing their cylinder position.
5. 5

   Remove cylinder head
   Remove cylinder head bolts in reverse sequence of installation pattern (typically from ends toward center). Use breaker bar if needed to break bolts free. Carefully lift cylinder head straight up off block to avoid damaging surfaces. Place head on clean workbench with combustion chambers facing up.
6. 6

   Compress valve spring and remove keepers
   Position cylinder head securely. Install valve spring compressor tool on the affected valve spring. Compress spring evenly until keepers are accessible. Use magnetic tool or needle-nose pliers to carefully remove both valve keepers. Slowly release spring compressor tension.
   ⚠Keep fingers clear of valve spring retainer path as spring is released; sudden movement can cause pinching injury
7. 7

   Remove valve spring components
   Remove valve spring retainer, valve spring, and valve spring seat (if equipped). Inspect valve stem for damage, scoring, or excessive wear. Do not remove valve from head unless replacement is also planned.
8. 8

   Install new valve spring
   Place new valve spring seat on cylinder head (if applicable). Install new valve spring over valve stem with closely-wound coils toward cylinder head (if spring has variable pitch). Position new retainer on top of spring.
9. 9

   Compress new spring and install keepers
   Using valve spring compressor, compress new spring until retainer groove on valve stem is fully exposed. Install both valve keepers in stem groove, ensuring they seat properly in retainer slots. Slowly release compressor while ensuring keepers remain seated. Tap retainer gently with soft mallet to confirm keepers are locked in place.
10. 10

    Clean and inspect head and block surfaces
    Thoroughly clean cylinder head deck surface and engine block deck surface using gasket scraper and solvent. Remove all old gasket material and carbon deposits. Inspect both surfaces for warping, cracks, or damage. Check head surface with straightedge if warping is suspected.
11. 11

    Install cylinder head
    Position new head gasket on block with correct orientation (check for TOP markings and coolant passage alignment). Carefully lower cylinder head onto block, aligning all bolt holes. Install head bolts with appropriate sealer on threads. Torque head bolts in three progressive stages following proper sequence (center outward in crisscross pattern): first to 50 ft-lbs, then 65 ft-lbs, and finally to manufacturer specification (approximately 95-105 ft-lbs for 390ci).
12. 12

    Reinstall rocker arm assembly
    Install pushrods in their original positions, ensuring they seat properly in lifter cups. Position rocker arm shaft assembly over studs. Install mounting bolts and torque evenly in multiple passes to manufacturer specification. Adjust valve lash on affected valve according to 390ci V8 specifications (typically 0.010" intake, 0.018" exhaust when cold).
13. 13

    Reinstall manifolds
    Install new exhaust manifold gasket and mount exhaust manifold to cylinder head, torquing bolts in sequence from center outward. Install new intake manifold gaskets on both cylinder heads (if applicable). Position intake manifold and install bolts, torquing in proper sequence from center outward to manufacturer specification (typically 35-40 ft-lbs).
14. 14

    Reinstall remaining components
    Install new valve cover gasket and reinstall valve cover, torquing bolts evenly to specification. Reinstall carburetor with new gasket. Reconnect all vacuum lines, electrical connectors, throttle linkage, and fuel line to original positions. Install spark plugs and reconnect spark plug wires in correct firing order. Reinstall air cleaner assembly.
15. 15

    Refill fluids and check for leaks
    Refill cooling system with appropriate coolant mixture. Refill engine with correct grade and quantity of oil. Reconnect battery. Start engine and check immediately for oil leaks, coolant leaks, and unusual noises. Allow engine to reach operating temperature and recheck all connections.

Reassembly

1. Double-check that all fasteners are torqued to specification, particularly head bolts and intake manifold bolts
2. Verify valve lash adjustment is correct on the repaired valve after engine reaches operating temperature
3. Recheck coolant and oil levels after initial warm-up cycle
4. After first 500 miles, retorque cylinder head bolts if using conventional head bolts (not torque-to-yield type)

Verification

• Start engine and listen for unusual valve train noise; valve spring should operate silently
• Check for oil leaks around valve cover, intake manifold, and cylinder head gasket
• Check for coolant leaks around head gasket and intake manifold
• Monitor oil pressure gauge to ensure normal pressure is maintained
• Test drive vehicle and verify normal engine performance with no misfires or power loss
• After cool-down, recheck valve cover bolts and intake manifold bolts for proper torque

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