Introduction: Unlocking 80 Extra Horsepower from Your Pontiac 455

The Pontiac 455 is a legendary big-block, known for its torque and durability. Yet even this stout engine leaves significant performance on the table with its factory camshaft. Swapping in a high-performance aftermarket camshaft—specifically a Lunati cam—is one of the most effective single modifications you can make. With a properly matched Lunati cam and supporting modifications, Pontiac enthusiasts routinely see gains of 70–80 horsepower at the crank, along with a much broader power band.

This guide provides a complete, step-by-step procedure for installing a Lunati camshaft in your Pontiac 455. It covers everything from tool selection and engine preparation to cam break-in and final timing checks. Whether you are a seasoned engine builder or a motivated do-it-yourselfer, following these instructions will help you achieve a reliable, high-output build without costly mistakes.

Tools and Materials Needed

Before starting, gather all necessary tools and parts. Using proper equipment saves time and prevents damage. The following list includes everything you will need for a successful cam swap.

  • Lunati camshaft kit – Choose a grind matched to your compression, induction, and intended RPM range. Lunati offers several profiles for the Pontiac 455; we recommend their high-lift street/strip series for the best balance of idle quality and power.
  • Torque wrench (ft-lb and in-lb) – Essential for fastening cam bolts, timing chain bolts, and rocker arm studs to factory specs.
  • Socket set (metric and SAE) – 3/8″ and 1/2″ drive sets will cover most fasteners; 15mm, 9/16″, and 1/2″ sockets are commonly needed.
  • Engine hoist or support bar – For removing the hood and lifting the front of the engine if needed.
  • Timing chain and gears – Upgrade to a roller timing set for improved accuracy and durability. A double-roller set is ideal for the Pontiac 455.
  • Cam bearing installation tool (if replacing cam bearings) – While not always required, installing fresh cam bearings is recommended when swapping lobes.
  • Gasket set – Intake manifold, valve cover, timing cover, and water outlet gaskets. Use a high-quality set from Fel-Pro or similar.
  • Assembly lube – Specifically for camshaft lobes and lifter bottoms. Avoid ordinary engine oil; use a dedicated cam lube like the Lunati assembly lube.
  • High-zinc break-in oil – Modern engine oils lack the zinc needed for flat-tappet cams. Use a purpose-built break-in oil (e.g., Driven BR30 or Brad Penn).
  • Oil filter and oil – Standard 5–6 quarts of break-in oil plus a new filter.
  • Plastic gauge (for checking cam-to-lifter clearance) – Verifies correct lobe taper and lifter rotation.
  • Feeler gauge, piston stop, degree wheel – For degreeing the cam after installation (optional but highly recommended).
  • Safety glasses and mechanic gloves – Protect yourself from debris, grease, and hot surfaces.

Preparation Steps

Proper preparation prevents problems and speeds up the actual cam swap. Follow these steps to get your Pontiac 455 ready.

Disconnect the Battery and Remove the Hood

Start by disconnecting the negative battery terminal to eliminate any risk of electrical shorts or accidental starter engagement. Then remove the hood for unobstructed access to the front of the engine. You can either unbolt the hood completely or prop it open with a support bar—removing it is safer and more convenient.

Drain Engine Oil and Remove Filter

Drain the engine oil into a suitable container. Remove the oil filter as well; you will install a new one later. This step prevents oil from spilling when you remove the timing cover and intake manifold.

Remove the Intake Manifold and Valve Covers

Unbolt the intake manifold using a 3/8″ socket (typically 15 mm or 9/16″). Lift the manifold clear and set it aside. Remove the valve covers to access the rocker arms and pushrods. Label each pushrod and rocker arm so you can reinstall them in the same location (or replace them with new parts).

Remove the Rocker Arms, Pushrods, and Lifters

Back off rocker arm adjusting nuts or bolts and remove the rocker arms. Take out the pushrods. If you plan to reuse the lifters, mark them with a felt-tip pen or store them in a numbered egg carton. Never swap lifters between lobes—each lifter has worn into its specific cam lobe.

Remove the Distributor and Fuel Pump (If Applicable)

Remove the distributor cap and distributor, noting its rotor position for later reinstallation. If your Pontiac 455 has a mechanical fuel pump, remove it now to clear the camshaft’s path.

Removing the Old Camshaft

With the top end stripped, you can now remove the old cam. Work slowly and methodically to avoid damage to the cam bearings or block.

Remove the Timing Chain Cover and Chain

Unbolt the timing chain cover. You may need to remove the harmonic balancer first using a puller. Once the cover is off, unbolt the cam gear (usually a single large bolt) and the crankshaft gear. Slide the timing chain and both gears off together. Inspect the chain for slack—if it’s stretched, a new height-adjustment roller chain is a worthwhile upgrade.

Unbolt the Old Camshaft

The camshaft is retained by a thrust plate or a retaining bolt. For most Pontiac 455 engines, a single large bolt holds the cam gear. Remove that bolt (often 7/16″ or 9/16″). Then carefully slide the old camshaft out of the front of the block. Rotate it slightly as you pull to avoid hitting the cam bearings. Use a long extension to reach through the block if necessary.

Inspect the Old Camshaft and Bearings

Examine the old cam lobes. Uneven wear, pitting, or visible galling indicates a lubrication problem or improper break-in. Check the cam journals for scoring. If the cam bearings show signs of failure or if the engine has high mileage, replace them now. Many Pontiac experts recommend installing new cam bearings whenever the cam is changed.

Installing the Lunati Camshaft

Now the exciting part: sliding in the new Lunati camshaft. This step demands patience and precision.

Pre-Lube the New Camshaft

Lunati camshafts come coated with a protective film, but you must apply assembly lube before installation. Coat every lobe, journal, and the distributor drive gear with a generous layer of moly-based assembly lube. Do not use standard engine grease—only a product designed for flat-tappet cams.

Slide the Camshaft In

Carefully insert the camshaft through the front of the block. Rotate it slowly to guide the journals through the bearings. Avoid touching the cam bearings with the lobe edges. If you feel resistance, stop and check alignment—never force it.

Install the Timing Chain and Gears

Place the new timing chain and gears onto the cam and crankshaft, aligning the timing marks according to the manufacturer’s instructions. For a Pontiac 455, the standard alignment is with the cam gear dot at 12 o’clock and the crank gear dot at 6 o’clock (straight up and down). Some roller chains use a keyway indexing system; follow the diagram supplied with your Lunati cam kit.

Torque Cam Bolt and Check End Play

Install the cam bolt and torque it to the manufacturer’s specification—typically 45–55 ft‑lb for a single bolt. Use a thread locker on the bolt threads. After torquing, check camshaft end play using a dial indicator or feeler gauge between the cam gear and the thrust plate. End play should be 0.002–0.006 inch. If it’s too tight, the thrust plate may need adjustment.

Install Lifters and Pushrods

Before fully assembling the top end, install the lifters. Dip each lifter in break-in oil before placing it in its bore. Install the pushrods and rocker arms finger-tight. Do not adjust valve lash yet—wait until the cam break-in stage.

Reassembling the Engine

With the cam in place, reassemble the engine carefully. Pay attention to torque sequences and gasket sealing.

Install Timing Cover and New Gasket

Clean the timing cover and cylinder block sealing surface thoroughly. Apply a thin bead of RTV silicone to the gasket corners (where the cover meets the oil pan and intake manifold). Install the timing cover and torque the bolts in a crisscross pattern to 15–20 ft‑lb.

Reinstall the Intake Manifold and Valve Covers

Place a new intake manifold gasket set onto the block. Apply a dab of RTV at the front and rear China walls. Install the intake manifold and torque the bolts in the factory sequence (usually starting from the center and working outward) to 30–40 ft‑lb in two steps. Install new valve cover gaskets and torque them evenly to 5–8 ft‑lb.

Reattach the Distributor and Fuel Pump

Install the distributor with the rotor pointing to the number one cylinder firing position (cylinder #1 at TDC on compression stroke). Reinstall the fuel pump if removed. Connect all vacuum lines and spark plug wires according to your Pontiac 455’s firing order (18436572).

Fill with Break‑In Oil and New Filter

Install a new oil filter. Fill the engine with 5–6 quarts of high‑zinc break‑in oil. Do not use synthetic oil during break‑in—the synthetic base lacks the necessary zinc for flat‑tappet cams. Priming the oil system with a drill-driven oil pump shaft is recommended before startup to ensure immediate oil flow to the cam and lifters.

Final Checks and Timing Verification

Before starting, perform these critical final checks.

Check Valve Lash (if adjustable)

If your Pontiac 455 uses adjustable rocker arms, set the intake valve lash to 0.000–0.000 (zero lash) plus the Lunati recommended preload (typically 1/2 to 3/4 turn past zero). Follow the rocker arm manufacturer’s specs.

Degreeing the cam verifies that the lobe centerlines match the manufacturer’s card. Use a degree wheel and a dial indicator on the number one intake lifter. If the valve events are off, an offset key or bushing can correct the cam timing. Lunati provides detailed degreeing instructions for their cams.

Verify Ignition Timing

Set the initial timing to 10–12° BTDC (base) with a timing light. For aggressive Lunati cams, you may need to adjust total timing to 34–36° at 3,000 rpm. Listen for detonation during test drive and adjust accordingly.

Check for Oil Leaks

Before firing the engine, inspect all gasket joints for gaps or loose bolts. Pay special attention to the timing cover, intake manifold ends, and valve cover seals.

Starting the Engine and Cam Break‑In

This is the most critical part of the entire process. A flat‑tappet cam requires a strict break‑in procedure to ensure the lobes and lifters mate properly.

Prime the Oil System

Insert a priming rod into the distributor hole and spin it with a heavy‑duty drill (at least 500 rpm) until oil flows from the pushrod oil holes. This can take 30–60 seconds. Stop priming only when you see consistent oil flow at all rocker arms.

Start the Engine and Run at Fast Idle

With the ignition system ready, start the engine. Immediately bring the RPM up to 2,000–2,500 rpm and hold it there for 20 minutes. Do not let the engine idle slowly; cam break‑in requires high oil splash to the lobes and lifters. If the engine misfires or stalls, restart immediately and bring the revs back up.

Monitor Oil Pressure and Temperature

During break‑in, oil pressure should be at least 30 psi hot. Watch for any unusual noises—a ticking lifter may need a preload adjustment. If the coolant temperature rises above 220°F, shut down and investigate coolant circulation.

After Break‑In, Change Oil and Filter

Once the 20‑minute break‑in is complete, shut down the engine. Immediately drain the break‑in oil (which will contain fine metal particles from the initial wear‑in). Install a new filter and fill with a high‑quality synthetic or conventional oil with adequate zinc for continued engine life.

Test Drive and Tune

After the initial break‑in, take the car for a test drive. Keep engine speeds moderate for the first 200 miles. Re‑torque the intake manifold bolts after the first heat cycle. Dial in the carburetor or EFI system for the new cam’s vacuum characteristics. You should feel a noticeable increase in power, especially in the mid‑range where the Lunati cam shines.

Conclusion: Reap the Rewards of Your Lunati Cam Swap

Installing a Lunati camshaft in your Pontiac 455 is one of the most rewarding engine modifications you can undertake. The 80‑horsepower gain is not just a number—it translates to quicker acceleration, stronger passing power, and a more exciting driving experience. By following this detailed guide, you have ensured that the installation is done correctly, with proper break‑in procedures and attention to detail. Your Pontiac 455 will run stronger, last longer, and deliver the performance you built it for.