Replacement of the exhaust flex pipe on a 1966 Chevrolet Corvette 327 V8, requiring exhaust system disassembly and welding or clamping of the new flex pipe section.

Warnings

Tools required

Parts

• Exhaust flex pipe (2" or 2.25" diameter, verify original) × 1 — Use OEM specification or performance equivalent
• Exhaust band clamps (if not welding) × 2 — 2" or 2.25" stainless steel
• Exhaust manifold flange gaskets × 2 — Use OEM specification
• Exhaust manifold bolts/studs (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and allow exhaust system to cool completely (minimum 2 hours after last operation).
2. Apply wheel chocks to rear wheels.
3. Spray all exhaust fasteners and connections with penetrating oil, allow to soak for at least 30 minutes (24 hours preferred).
4. Raise front of vehicle using floor jack at frame rail jacking points.
5. Secure vehicle on jack stands rated for vehicle weight, positioned at frame rails behind front wheels.
6. Inspect exhaust system to identify exact location of flex pipe and determine if welded or clamped installation will be used.
7. Measure existing flex pipe diameter and length if replacing existing component.
8. Disconnect negative battery cable if working near starter or electrical components.

Procedure

1. 1

   Access and inspect exhaust system
   Position yourself under the vehicle with adequate lighting. Locate the flex pipe section in the exhaust system (typically between exhaust manifolds and intermediate pipes on modified systems). Inspect all connecting points, hangers, and surrounding components. Take photographs for reference during reassembly. Verify clearance to fuel lines, brake lines, and body panels.
2. 2

   Disconnect upstream exhaust connection
   If flex pipe connects directly to exhaust manifolds or headers, remove the collector flange bolts. The 1966 Corvette 327 typically uses a 2-bolt flange at each manifold collector, but verify the exact arrangement on this vehicle. Measure the flange fastener heads to determine the correct wrench/socket size before removal, then remove the flange fasteners per side. If bolts are seized, apply heat carefully with a torch while protecting nearby components. Support the exhaust pipe with a jack stand or helper to prevent stress on other connections.
3. 3

   Disconnect downstream exhaust connection
   Locate the downstream connection point of the flex pipe (typically where it meets the intermediate pipe or H-pipe). If clamped, loosen the band clamp bolts completely and slide clamps away from joint. If welded, mark the cut line with soapstone or marker at least 2 inches behind the flex pipe to preserve usable pipe. Support the rear exhaust section with a jack stand before making cuts.
4. 4

   Remove exhaust hangers
   Identify all rubber exhaust hangers supporting the section being removed. Use an exhaust hanger removal tool or pry bar to carefully unhook each rubber hanger from its mounting bracket. Identify and note the actual exhaust hanger locations on this C2 chassis, as hanger positions vary by configuration; verify each hanger location before unhooking. Work carefully to avoid tearing rubber isolators that will be reused.
5. 5

   Cut or separate flex pipe section
   If welded, use a reciprocating saw with metal cutting blade or exhaust pipe cutter to cut through the pipe at marked locations. Make cuts perpendicular to pipe centerline for clean mating surfaces. If clamped, separate the slip joint connections. Remove the old flex pipe section completely from the vehicle. Inspect remaining pipe ends for damage, rust, or distortion that would prevent proper seal.
6. 6

   Prepare pipe ends for new flex pipe
   Clean all mating surfaces thoroughly with a wire brush, removing rust, carbon deposits, and old gasket material. If welding, clean back to bare metal for at least 1 inch from the cut edge. Check pipe diameter with measuring tape or calipers to confirm new flex pipe sizing. File or grind any burrs or sharp edges from cut pipes. Ensure pipe ends are round and not crushed or distorted.
7. 7

   Test fit new flex pipe
   Position the new flex pipe between the prepared pipe ends without fastening. Verify correct length, diameter, and orientation. The flex section should be positioned to accommodate engine movement without binding or over-extending. Confirm minimum 1 inch of overlap on each end for clamped installations, or proper gap (1/8 inch) for welded installations. Check clearance to frame, body panels, driveshaft, and suspension components through full range of motion.
8. 8

   Install flex pipe upstream connection
   Position the flex pipe at the upstream connection point. If connecting to manifold/header collectors with flanges, install new gaskets and align bolt holes. Hand-start all flange bolts before tightening. Tighten the collector flange fasteners per side in an alternating pattern to ensure even gasket compression, after confirming the actual fastener count on this flange. If welding or clamping to pipe, position with correct overlap and alignment before securing.
9. 9

   Secure downstream connection
   Align the downstream end of the flex pipe with the intermediate pipe section. For clamped installation, slide the new band clamp over the joint with adequate overlap on both pipes, then tighten clamp bolts evenly in alternating pattern until joint is secure and sealed. For welded installation, tack weld at 4 points around circumference, verify alignment, then complete full circumferential weld with proper penetration.
10. 10

    Reinstall exhaust hangers
    Reattach all rubber exhaust hangers to their mounting brackets, ensuring the exhaust system hangs at proper height and angle. The system should be supported without stress or binding at any connection point. Verify adequate clearance to chassis, body, driveshaft, and suspension components. Adjust hanger positions if necessary to achieve proper alignment.
11. 11

    Inspect all connections and clearances
    Perform final visual inspection of all exhaust connections, welds, or clamps. Check that all flange bolts are tight and gaskets are properly seated. Verify the flex pipe is not kinked, over-extended, or compressed. Confirm minimum 1 inch clearance to all chassis components, fuel lines, brake lines, and wiring. Check that exhaust system can move freely without binding on suspension travel.

Reassembly

1. Reconnect negative battery cable if disconnected.
2. Remove jack stands and carefully lower vehicle to ground.
3. Double-check all fasteners and connections are secure before starting engine.

Verification

• Start engine and allow to idle. Listen for exhaust leaks at all connection points, particularly at flex pipe joints and flange connections.
• With engine running, have an assistant slightly rev engine while observing flex pipe movement and clearances. Flex pipe should compress and extend smoothly without binding.
• Check for any contact between exhaust system and chassis, body, or suspension components during engine movement.
• Inspect all welds or clamps for signs of leakage (visible exhaust smoke or soot).
• Test drive vehicle and listen for any exhaust rattles, leaks, or contact noises. Recheck all connections after test drive.
• After 50-100 miles of driving, reinspect all exhaust fasteners and retighten if necessary as exhaust system heat cycles can cause settling.

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