Exhaust Pipe - Rear Section

Replacement of the rear exhaust pipe section on a 1966 Corvette 327ci V8, from the intermediate pipe connection to the rear muffler outlet.

Warnings

Tools required

Parts

• Rear exhaust pipe section × 1 — Use OEM specification or Walker/Dynomax equivalent
• Exhaust flange gasket (2.25" or 2.5" depending on pipe diameter) × 2 — Fel-Pro 60985 or equivalent
• Exhaust flange bolts and nuts × 4 — 3/8"-16 x 1.25" stainless steel
• Exhaust hanger insulators (if deteriorated) × 2 — Use OEM specification

Preparation

1. Ensure engine and exhaust system are completely cold to the touch
2. Park vehicle on level surface and apply parking brake
3. Place wheel chocks behind rear wheels
4. Raise rear of vehicle with floor jack and support securely on jack stands under frame rails
5. Spray all exhaust flange bolts and hanger connections with penetrating oil and allow to soak for 15-30 minutes

Procedure

1. 1

   Access and inspect rear exhaust section
   Position yourself under the rear of the vehicle with adequate lighting. Locate the rear exhaust pipe section running from the intermediate (over-axle) pipe flange connection toward the rear of the vehicle, including the muffler and tailpipe outlet. Inspect the condition of all flange connections, hangers, and the pipe itself for rust-through or damage. Identify the two exhaust hanger points supporting the rear section. Inspect the condition of all flange connections, hangers, and the pipe itself for rust-through or damage. Identify the two exhaust hanger points supporting the rear section.
2. 2

   Disconnect rearmost flange connection
   Starting at the rear, locate the flange connection at the muffler outlet or tailpipe junction. Using a 9/16" wrench, remove the 2 flange bolts and nuts securing this connection (if the joint is a slip-fit clamped connection rather than a flange, loosen the U-bolt clamp nuts instead). If fasteners are severely corroded, apply additional penetrating oil and use a wire brush to clean threads. If bolts break or cannot be removed, cut them with a hacksaw or reciprocating saw flush with the flange.
3. 3

   Remove rear exhaust hanger
   Locate the rearmost rubber exhaust hanger insulator supporting the pipe. Using a large flat-blade screwdriver or exhaust hanger tool, pry the pipe hanger rod out of the rubber insulator bushing. Work carefully to avoid tearing the rubber if it will be reused. If the insulator is cracked or deteriorated, plan to replace it during reassembly.
4. 4

   Disconnect intermediate flange connection
   Move forward to the intermediate pipe flange connection (where the rear section connects to the mid-pipe or resonator). Remove the 2 flange bolts and nuts using a 9/16" wrench (if this is a clamped slip-joint connection, loosen the U-bolt clamp nuts instead). Keep steady back-pressure on the wrench to prevent rounding of corroded fastener heads. If fasteners cannot be removed intact, cut them off and plan to replace with new hardware.
5. 5

   Remove forward exhaust hanger
   Locate the forward rubber exhaust hanger insulator supporting the rear pipe section. Pry the hanger rod out of the rubber bushing using a screwdriver or exhaust hanger tool. The pipe should now be free to remove.
6. 6

   Remove rear exhaust pipe section
   With all connections and hangers disconnected, maneuver the rear exhaust pipe section downward and rearward to clear the vehicle. The pipe may require rotation or angling to navigate past crossmembers and suspension components. If the pipe is seized in place despite all fasteners being removed, use a rubber mallet to tap the flanges gently to break the seal.
7. 7

   Clean and inspect flange surfaces
   Using a wire brush, thoroughly clean both flange surfaces on the intermediate pipe and rear muffler/tailpipe connections. Remove all remnants of old gasket material, carbon buildup, and surface rust. Inspect flange surfaces for warping, cracks, or excessive corrosion. Minor surface pitting is acceptable, but severe damage will cause exhaust leaks.
8. 8

   Inspect and replace exhaust hangers
   Inspect both rubber exhaust hanger insulators for cracks, tears, or compression damage. The rubber should be pliable, not hard and brittle. Replace any deteriorated hangers. Check that the frame-mounted hanger brackets are secure and not rusted through.
9. 9

   Prepare new exhaust pipe
   Compare the new rear exhaust pipe section to the removed part to verify correct length, diameter, and hanger placement. Apply a thin coat of high-temperature anti-seize compound to all flange bolt threads and the first 3-4 threads inside the nuts. Position new flange gaskets on both connection points.
10. 10

    Install rear exhaust pipe section
    Maneuver the new rear exhaust pipe section into position, routing it through the same path as the original. Align the forward flange with the intermediate pipe connection first, inserting flange bolts finger-tight only. Then align the rear flange connection and insert those bolts finger-tight. Do not fully tighten any fasteners yet.
11. 11

    Install exhaust hangers
    With the pipe hanging loosely on finger-tight bolts, install the hanger rods into the rubber insulator bushings. You may need to lift or shift the pipe slightly to align the hangers. Use a screwdriver to lever the rubber bushing open if necessary. Ensure both hangers are fully seated.
12. 12

    Align and tighten flange connections
    With hangers installed, check that the exhaust pipe has adequate clearance from the frame, suspension components, and body panels (minimum 1 inch clearance recommended). Adjust pipe position by loosening hangers slightly if needed. Once properly aligned, tighten all 4 flange bolts in a criss-cross pattern to secure the connections, targeting approximately 20-25 ft-lbs for 3/8"-16 hardware. Tighten firmly to ensure a leak-free seal, but avoid over-torquing which can warp the flanges or break studs on this older exhaust system.
13. 13

    Final clearance inspection
    Perform a final walk-around inspection under the vehicle. Verify the exhaust pipe has adequate clearance from all chassis components, suspension parts, fuel lines, and brake lines. Shake the pipe gently by hand to ensure hangers are properly supporting it and there is no excessive movement or contact points.

Reassembly

1. Lower vehicle from jack stands carefully
2. Remove wheel chocks
3. Start engine and allow to idle while listening for exhaust leaks at flange connections
4. If leaks are detected, allow system to cool and re-torque flange bolts or inspect gasket seating

Verification

• Start engine and listen for exhaust leaks at both flange connections - there should be no hissing or popping sounds
• Perform a test drive and listen for any rattling or contact between exhaust and chassis
• After test drive, re-inspect all clearances and connections with the exhaust system at operating temperature (allow to cool before touching)
• Verify no exhaust odor is entering the cabin during operation

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