Introduction: Why Upgrade to the Trick Flow Intake Manifold on Your Chevy LS1

The Chevy LS1 engine is known for its robust design, but the factory plastic intake manifold has limitations in airflow and temperature management. The Trick Flow intake manifold is a direct-fit aftermarket replacement engineered to improve volumetric efficiency, reduce intake air temperatures, and support higher horsepower levels—especially when combined with cams, headers, or forced induction. This upgrade typically yields gains of 15–25 horsepower on an otherwise stock LS1, with noticeable improvements in throttle response and top-end power.

This guide provides a detailed, step-by-step method for installing the Trick Flow intake manifold on a Chevrolet LS1. The process is straightforward for a competent DIY mechanic but requires attention to torque specs, gasket preparation, and careful component reconnection. Follow each section to ensure a leak-free, reliable installation that maximizes performance.

Tools and Materials Needed

Gather all tools and supplies before starting. Using the correct tools prevents damage to the new manifold and ensures proper torque application.

  • Trick Flow Intake Manifold Kit (includes manifold, gaskets, bolts, and possibly a throttle body spacer if ordered)
  • Torque Wrench (1/2-inch drive, capable of 10–35 lb-ft; a 3/8-inch drive is also useful for smaller bolts)
  • Socket Set – metric and SAE: common sizes include 8mm, 10mm, 13mm, 15mm, and 18mm
  • Ratchet and Extensions (6-inch and 12-inch extensions recommended)
  • Gasket Scraper (plastic or razor blade type – avoid scratching aluminum surfaces)
  • Clean Rags and Brake Cleaner (to degrease sealing surfaces)
  • Engine Oil (for lubricating gaskets; use clean 5W-30 or assembly lube)
  • Thread Sealant (for coolant ports and vacuum fittings if present)
  • Fuel Line Disconnect Tool (for LS1 fuel rail – 3/8-inch or 5/16-inch depending on year)
  • Catch Pan (for coolant if you choose to drain it – recommended to avoid mess)
  • Paint Pen or Masking Tape (for labeling hoses and connectors)
  • Shop Manual or Torque Spec Chart (factory LS1 intake bolts: 89 in-lb or ~7.4 lb-ft; Trick Flow may specify different values – follow included instructions)

Preparation Steps

Workspace and Vehicle Setup

  • Park the vehicle on a level surface and allow the engine to cool completely. A hot engine can cause burns and warps gasket surfaces.
  • Disconnect the negative battery cable and isolate it to prevent accidental contact.
  • Relieve fuel system pressure: remove the fuel pump fuse or relay, start the engine, and let it stall. Crank once more to confirm pressure is gone. Reinstall the fuse afterward.

Remove Components Obstructing Access

  • Air Intake Assembly: Unbolt the intake tube, mass air flow sensor, and air filter box.
  • Throttle Body: Disconnect the throttle cable (or drive-by-wire connector), vacuum hoses, and coolant lines (if equipped). Remove the four bolts and set the throttle body aside. Cover the intake opening to prevent debris from falling in.
  • Fuel Rail and Injectors: Unplug all injector electrical connectors. Use the fuel line disconnect tool to separate the fuel feed and return lines. Unbolt the fuel rail brackets and lift the rail with injectors attached. Protect the injector tips with caps or a clean rag.
  • Ignition Coils: On LS1 engines, the coils are mounted on the valve covers. Remove them carefully and set aside without disturbing the spark plug wires.
  • Vacuum Lines, Wiring Harnesses, and PCV Hoses: Trace and label each connection with tape or a paint pen. Common connections include the brake booster, MAP sensor, EVAP canister, and PCV valve.
  • Coolant Crossover and Heater Hoses: If your LS1 has coolant lines to the throttle body or intake (some years do), clamp them off and disconnect. Draining coolant is not strictly necessary but prevents spills.

Removing the Old Intake Manifold

With all peripherals removed, the factory intake manifold is ready to come off.

Loosening Bolts

  • Using a 10mm socket and ratchet, remove the eight intake manifold bolts in a reverse cross pattern (outside in). This prevents warping the plastic manifold.
  • If bolts are stuck, use penetrating oil and allow time to soak.

Lifting the Manifold

  • Gently rock the manifold side to side to break the gasket seal. Do not pry against the cylinder head or block with metal tools.
  • Lift the manifold straight up and off the engine. Be mindful of the knock sensor harness and engine harness that may be trapped underneath.

Cleaning Mating Surfaces

  • Use a gasket scraper and brake cleaner to remove all old gasket material from the cylinder heads and engine valley. Be thorough—remaining debris can cause vacuum leaks.
  • Inspect the valley cover (if exposed) for any cracks or damage. The LS1 uses a steel valley cover; it is fine as-is.
  • Wipe the surfaces with a lint-free cloth until they are clean and dry.

Installing the Trick Flow Intake Manifold

Gasket Preparation

  • The Trick Flow kit typically includes silicone or paper gaskets. Apply a thin, even coat of clean engine oil to both sides of each gasket. This helps them compress evenly and prevent sticking on future removals.
  • Place the gaskets onto the cylinder head intake ports. They should align perfectly; if not, confirm the manifold is for an LS (not LT) engine.

Manifold Positioning

  • Carefully lower the Trick Flow intake manifold into place. Ensure the intake ports seat fully onto the gaskets. The bolt holes should align without force.
  • Insert the bolts (M8 or M6 depending on model). Hand-tighten them initially to hold the manifold in position.

Torque Sequence and Specifications

Proper bolt torque is critical to prevent vacuum leaks. Use a torque wrench and follow a cross pattern. For most LS1 intake manifolds, the specification is 89 in-lb (7.4 lb-ft). However, Trick Flow may recommend a slightly different value—always refer to the instruction sheet included with your kit. The typical sequence from center outward:

  1. Passenger front (near cylinder #1)
  2. Driver rear (near cylinder #7)
  3. Passenger rear (near cylinder #3)
  4. Driver front (near cylinder #5)
  5. Passenger middle-front (near cylinder #2)
  6. Driver middle-rear (near cylinder #8)
  7. Passenger middle-rear (near cylinder #4)
  8. Driver middle-front (near cylinder #6)

Torque each bolt to the specified value, making three passes: first to 50%, second to 75%, third to full torque. Recheck after 15 minutes.

Important: Do not overtighten. The Trick Flow manifold is likely cast aluminum; overtightening can strip threads or crack the intake.

Reconnecting Components

Fuel Rail and Injectors

  • Install fresh O-rings on the injectors (if not already done). Lubricate them with engine oil for easy insertion into the intake manifold fuel rail pockets.
  • Seat the fuel rail into the manifold, pressing each injector fully into place. Secure with the rail bolts (torque to 89 in-lb, or as specified).
  • Connect the fuel lines using the quick-connect tool. Push until you hear a click, then tug to confirm retention.
  • Reconnect injector electrical connectors.

Throttle Body and Intake Ducting

  • If your Trick Flow manifold requires a throttle body gasket, use a new one (often included). Torque the throttle body bolts to 89 in-lb.
  • Reattach the throttle cable or electronic connector. Adjust cable tension if necessary.
  • Reconnect the mass air flow sensor and intake tube to the throttle body.

Vacuum Lines and Electrical Connections

  • Refer to your labeling: attach the MAP sensor, PCV line, brake booster, and any other vacuum hoses. Use small zip ties if hoses are loose.
  • Secure the engine harness away from hot surfaces (exhaust manifolds).
  • Reinstall the ignition coils and their wiring.

Coolant System

  • If you disconnected coolant lines, reconnect them and tighten hose clamps.
  • Refill the radiator with the proper coolant mixture (50/50 Dex-Cool or equivalent). Burp the system after starting.

Final Checks Before Starting

  • Inspect all fasteners: intake manifold bolts, throttle body bolts, fuel rail bolts.
  • Verify no tools, rags, or debris are in the engine bay, especially under the intake.
  • Reconnect the negative battery terminal.
  • Check oil level and coolant level. Top off as needed.
  • Turn the ignition key to the "ON" position (without cranking) to prime the fuel pump. Listen for the pump running. Repeat three times to pressurize the fuel system.
  • Inspect fuel lines and fittings for leaks before attempting to start.

Starting the Engine and Initial Testing

First Start Procedure

  • Crank the engine. It may take a few extra revolutions to build fuel pressure and oil pressure initially.
  • Once running, allow the engine to idle at around 1000–1200 RPM for the first 30 seconds. Listen for any unnatural hissing (vacuum leak) or ticking (exhaust leak).
  • Check for fuel, oil, or coolant leaks around the intake manifold and fuel rails.
  • Monitor the temperature gauge. Normal operating temperature should be reached within 5–10 minutes of idle.

Post-Start Checks

  • Rev the engine gently to 2500 RPM and listen for consistent idle return. A vacuum leak will cause a high idle or erratic idle.
  • Use a smoke machine or propane tester to locate small vacuum leaks around gasket areas if idle is unstable.
  • If the engine stumbles or misfires, recheck injector connectors and spark plug wire routing.

Performance Tuning and Follow-Up

The Trick Flow manifold is designed to work with the stock engine control unit, but for maximum performance, a tune is recommended. The increased airflow may cause the engine to run lean at higher RPMs, potentially leading to knock. Have your vehicle tuned by a professional using HP Tuners or EFI Live software. Typical adjustments include fuel tables, ignition timing, and idle airflow settings.

After 500 miles, retorque the intake manifold bolts. The gaskets will compress over time, and a second torque pass ensures a lasting seal. Recheck all vacuum hoses and electrical connections.

Conclusion

Installing the Trick Flow intake manifold on your Chevy LS1 is a rewarding upgrade that delivers measurable power gains and improved throttle response. By following this step-by-step guide—paying close attention to gasket preparation, torque sequence, and proper reconnection of peripherals—you can achieve a reliable, leak-free installation. Remember that a tune will unlock the full potential of the manifold. With the correct tools and patience, this project can be completed in a weekend by an intermediate mechanic.

External Resources