Complete procedure to replace the head gasket on one cylinder bank of a 1966 Chevrolet Corvette 327ci V8, including cylinder head removal, surface preparation, and reassembly with proper torque sequence.

Warnings

Tools required

Parts

• Cylinder head gasket (single) × 1 — Use OEM specification
• Cylinder head bolt set (TTY type) × 1 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification
• Exhaust manifold gasket × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Coolant bypass hose (if deteriorated) × 1 — Use OEM specification
• Thermostat housing gasket × 1 — Use OEM specification
• Anti-seize compound × 1 — Copper or nickel-based high-temp

Fluids

• 5W-30 Conventional Engine Oil — 5 qt
• DEX-COOL Extended Life (Orange) Coolant — 10 qt

Preparation

1. Park vehicle on level surface and allow engine to cool completely for minimum 2 hours.
2. Disconnect negative battery cable to prevent electrical shorts.
3. Drain engine coolant completely by opening radiator petcock and removing lower radiator hose.
4. Drain engine oil to prevent contamination during head removal.
5. Remove air cleaner assembly and label all vacuum lines for reinstallation.
6. Document spark plug wire routing and label each wire with cylinder number.
7. Take photographs of accessory bracket positions and hose routing for reference during reassembly.

Procedure

1. 1

   Remove intake manifold
   Disconnect fuel line at carburetor (use two wrenches to prevent twisting the line). Remove throttle linkage and transmission kickdown cable if equipped. Disconnect all vacuum lines, coolant hoses, and electrical connections from intake manifold. Remove the intake manifold mounting bolts (12 total) and carefully lift manifold away from engine. Inspect manifold gasket surfaces for damage.
2. 2

   Remove valve cover and rocker assembly
   Remove valve cover retaining bolts (6 total) and lift off valve cover. Remove rocker arm nuts (8 per head) while keeping rocker arms, balls, and pushrods in order for reinstallation in original positions. Store pushrods in numbered holder or cardboard template to maintain cylinder position. Inspect pushrod ends and rocker arm contact surfaces for wear.
3. 3

   Disconnect exhaust manifold
   Working from underneath vehicle if necessary, remove exhaust pipe flange bolts connecting exhaust pipe to manifold. Remove exhaust manifold retaining nuts (5 per manifold) and separate manifold from cylinder head. If manifold is seized to studs, apply penetrating oil and allow to soak before attempting removal. Inspect manifold for cracks and warpage.
4. 4

   Remove cylinder head bolts
   Remove the 17 cylinder head bolts in reverse of tightening sequence (outside to inside pattern). Loosen each bolt gradually in multiple passes rather than removing one bolt completely at a time to prevent head distortion. Keep bolts in order if inspecting, but note that all head bolts must be replaced with new TTY bolts during reassembly. If bolts are difficult to remove, apply penetrating oil and allow to soak.
5. 5

   Remove cylinder head
   Carefully break cylinder head loose from block using a pry bar on designated pry points (never pry on gasket surfaces). Lift cylinder head straight up to avoid damaging deck surface. Place head gasket-side up on clean padded surface. Remove and discard old head gasket. Inspect lifter valley for coolant or oil contamination indicating gasket failure location.
   ⚠Cylinder head weighs approximately 50-60 pounds. Use proper lifting technique or get assistance to avoid injury.
6. 6

   Clean and inspect mating surfaces
   Use plastic gasket scraper to remove all gasket material from cylinder head and block deck surfaces. Clean surfaces thoroughly with brake cleaner or parts solvent. Use straight edge and feeler gauge to check both head and block surfaces for warpage. Maximum allowable warpage is 0.003 inches across entire surface. Check for cracks in combustion chambers and coolant passages. Any warpage or cracks requires professional machining or head replacement.
   ⚠Never use metal scrapers or abrasive pads on aluminum surfaces as this will cause surface damage and gasket sealing failure.
7. 7

   Inspect and measure cylinder bores
   With head removed, inspect cylinder bore surfaces for scoring, ridge wear at top of ring travel, and glazing. Wipe bores clean and check for pitting or corrosion. If performing leak-down or compression test after reassembly, note any concerns now. Verify all bolt holes in block are clean and dry with no coolant or oil present.
8. 8

   Install new head gasket
   Verify block deck and cylinder head surfaces are completely clean and dry. Position new head gasket on block with 'TOP' or 'FRONT' markings visible and correctly oriented. Align all coolant and oil passages carefully. Do not use any gasket sealant unless specifically required by gasket manufacturer. Ensure all head bolt holes align properly with gasket openings.
   ℹ️Some replacement gaskets are marked for front/rear orientation. Verify correct positioning before placing head.
9. 9

   Install cylinder head
   Carefully lower cylinder head onto block, aligning all bolt holes and guiding head onto dowel pins if equipped. Ensure head seats fully on gasket without shifting gasket position. Inspect around perimeter to verify gasket has not moved during head installation. Insert all new head bolts finger-tight in their correct positions before beginning torque sequence.
   ⚠Do not allow cylinder head to slide across gasket surface during installation as this can damage gasket and cause leaks.
10. 10

    Torque cylinder head bolts - Step 1
    Using torque wrench, tighten all 17 cylinder head bolts to 30 lb-ft (40 Nm) following the proper tightening sequence from center outward. Start with center bolts and work toward outer bolts in the specified pattern. Complete this step on all bolts before proceeding to next torque step.
    Torque spec

    Cylinder Head Bolts - Step 140 Nm (30 lb-ft)
11. 11

    Torque cylinder head bolts - Step 2
    Following the same tightening sequence, torque all cylinder head bolts to 59 lb-ft (80 Nm). Maintain the sequence pattern and ensure each bolt reaches specified torque before moving to next bolt.
    Torque spec

    Cylinder Head Bolts - Step 280 Nm (59 lb-ft)
12. 12

    Torque cylinder head bolts - Step 3
    Using angle gauge or torque angle meter, rotate each bolt an additional 90 degrees following the same tightening sequence. Mark each bolt head with paint or marker before rotation to verify full 90-degree turn. This is a critical step for TTY bolt proper clamping force.
    ⚠Angle tightening is cumulative. Each bolt receives one 90-degree rotation in this step. Do not repeat on same bolt.
    Torque spec

    Cylinder Head Bolts - Step 30 Nm (0 lb-ft) + 90°
13. 13

    Torque cylinder head bolts - Step 4
    Perform final 90-degree rotation on each cylinder head bolt following the same sequence. Each bolt will have received two 90-degree rotations (total 180 degrees beyond initial torque). Verify all bolts have been angle-tightened by checking paint marks.
    Torque spec

    Cylinder Head Bolts - Step 40 Nm (0 lb-ft) + 90°
14. 14

    Install pushrods and rocker assembly
    Apply engine assembly lube or clean engine oil to pushrod ends. Install each pushrod in its original location, ensuring lower end seats properly in lifter cup. Install rocker arms with pivot balls in correct positions. Apply engine oil to rocker arm contact points and tighten rocker arm nuts to proper preload - typically until pushrod can just barely be rotated with fingers, then 1/2 turn additional. Rotate engine two complete revolutions by hand to verify valve train operation.
15. 15

    Install exhaust manifold
    Install new exhaust manifold gasket on cylinder head studs. Position exhaust manifold and install retaining nuts finger-tight. Apply anti-seize compound to threads. Torque exhaust manifold nuts to 18 lb-ft (25 Nm) working from center outward. Connect exhaust pipe to manifold flange using new gasket and torque flange bolts to specification.
    Torque spec

    Exhaust Manifold Nuts25 Nm (18 lb-ft)
16. 16

    Install intake manifold
    Install new intake manifold gaskets on cylinder heads, ensuring proper orientation and alignment with all ports. Apply small bead of RTV sealant at front and rear block-to-head joints if specified by gasket manufacturer. Position intake manifold carefully to avoid disturbing gaskets. Install all manifold bolts finger-tight, then torque to 18 lb-ft (25 Nm) following proper sequence (center bolts first, working outward in a circular pattern).
    Torque spec

    Intake Manifold Bolts25 Nm (18 lb-ft)
17. 17

    Install valve cover and reconnect components
    Install new valve cover gasket in valve cover or on cylinder head as designed. Position valve cover and install retaining bolts, torquing to specification (typically 45-60 in-lbs). Reconnect all vacuum lines, coolant hoses, fuel line, throttle linkage, and electrical connections per labels and photos from disassembly. Install spark plug wires in correct firing order.
18. 18

    Refill fluids and prepare for startup
    Install new engine oil filter and refill crankcase with 5 quarts of 5W-30 conventional motor oil. Refill cooling system with 10 quarts of DEX-COOL extended life coolant mixed 50/50 with distilled water. Reconnect negative battery cable. Check all connections for security and verify no tools or parts remain in engine compartment.

Reassembly

1. Double-check all torque specifications have been met, particularly cylinder head bolts including angle tightening steps.
2. Verify all electrical connections, vacuum lines, and hoses are properly reconnected per documentation from disassembly.
3. Check cooling system for proper fill level and bleed all air from system per factory procedure.
4. Prime oil system by cranking engine with coil wire disconnected until oil pressure registers on gauge.

Verification

• Start engine and allow to reach operating temperature while monitoring for coolant, oil, or exhaust leaks.
• Check for abnormal engine noises including valve train noise, knocking, or ticking that would indicate improper assembly.
• Verify cooling system maintains proper temperature and thermostat opens correctly (upper radiator hose should become hot).
• After initial heat cycle, recheck valve cover and intake manifold bolt torque when engine is cold.
• Perform compression test or leak-down test to verify head gasket is sealing properly across all cylinders.
• Monitor oil level and condition for first 100 miles to detect any coolant contamination.
• Check for exhaust leaks at manifold flange after thermal cycling.
• Recheck coolant level after several heat cycles as air pockets work out of system.

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