Pontiac 455 Engine Mods: Installing a Ram Air III Cam for Improved Power

The Pontiac 455 is one of the most legendary big-block engines ever built, renowned for its massive low-end torque and reliable power that made it a favorite in muscle cars like the GTO, Firebird, and Grand Prix. But even a factory 455 can benefit from thoughtful upgrades. Among the most effective modifications is swapping the camshaft — and the Ram Air III profile stands out as a proven choice for enthusiasts seeking a substantial boost in horsepower and throttle response without sacrificing street manners. This guide walks through the complete installation process, from preparation through final tuning, so you can unlock the full potential of your Pontiac 455 with a Ram Air III camshaft.

Understanding the Ram Air III Camshaft

The Ram Air III camshaft was originally developed for Pontiac’s high‑performance engines in the late 1960s, most notably the 400‑cu‑in Ram Air III GTO. Its specifications deliver a classic muscle car powerband: strong mid‑range punch, a crisp idle, and an unmistakable exhaust note. The stock Pontiac 455 camshaft is mild by comparison, focusing on smooth low‑rpm operation at the expense of top‑end power. Upgrading to a Ram Air III profile transforms the engine’s character.

Key Specifications

Typical Ram Air III cam specs (for a factory reproduction grind) include:

  • Duration at 0.050″ lift: 227°/239° (intake/exhaust)
  • Valve lift (with 1.5:1 rockers): 0.470″/0.480″
  • Lobe separation angle: 113°

These numbers represent a noticeable step up from the stock 455 cam (approx. 204°/214° duration at 0.050″ with 0.413″/0.413″ lift). The extra duration and lift allow the cylinders to breathe better at higher rpm, while the 113° lobe separation helps maintain decent vacuum for brake boost and idle quality.

Performance Gains

  • Peak horsepower increases of 30–50 hp (depending on other engine components)
  • Torque curve shifts higher in the rpm range, with improved output above 3,000 rpm
  • Sharper throttle response, especially in the mid‑range
  • Classic, aggressive exhaust note that screams “Pontiac”

The Ram Air III cam is a well‑balanced street/strip profile. For comparison, a full Ram Air IV or solid lifter grind would yield more top‑end power but would require additional supporting mods (higher compression, ported heads, larger carburetor) and would be less street‑friendly. The Ram Air III is an ideal upgrade for a 455 that retains factory heads and intake.

Tools and Materials Needed

Before starting the installation, gather everything you need. A complete job requires both standard hand tools and some Pontiac‑specific items. Having quality tools on hand makes the process safer and reduces the chance of component damage.

Required Parts

  • Ram Air III camshaft (from a reputable supplier such as Butler Performance or Comp Cams)
  • New lifters (recommended: replace lifters and cam together to ensure proper break‑in)
  • Timing chain and gears (a double‑roller set is preferred for durability)
  • Engine gasket set (intake manifold, valve covers, timing cover)
  • Assembly lube (high‑pressure, zinc‑rich oil is also essential for break‑in)
  • Fresh engine oil (break‑in oil with high zinc content is critical)
  • Coolant (if removing water pump for access)

Required Tools

  • Socket set (standard and metric), ratchets, extensions
  • Torque wrench (ft‑lb and in‑lb ranges)
  • Camshaft degreeing kit (optional but highly recommended for precise installation)
  • Dial indicator and magnetic base (for verifying piston‑to‑valve clearance)
  • Timing light
  • Oil filter wrench
  • Pry bar (for carefully removing harmonic balancer)
  • Clean rags and solvent for cleaning old gasket surfaces

Preparation Steps

Proper preparation is the difference between a smooth install and a headache. Take your time here — rushing often leads to mistakes that can damage the new cam or your engine.

Disconnect the Battery and Drain Fluids

Safety first: disconnect the negative battery cable to prevent accidental starting or short circuits. Drain the engine oil and remove the oil filter. If you’ll be removing the water pump (recommended for better access to the timing cover), also drain the coolant.

Remove Ancillary Components

  • Intake manifold: unbolt and lift off, being careful with gasket surfaces.
  • Valve covers: remove and set aside.
  • Rocker arms and pushrods: label or store in order for re‑use if keeping the same rockers.
  • Distributor: note the rotor position for re‑installation; remove the distributor hold‑down and pull it straight up.
  • Water pump and harmonic balancer: unbolt the balancer with a puller if needed.
  • Timing cover: remove all bolts and gently pry off; replace the front seal while you’re there.

Mark Timing Chain Position

Before removing the old chain, rotate the engine to Top Dead Center (TDC) on cylinder #1. Mark the relationship between the camshaft gear and crankshaft gear for reference. A paint pen or scribe works well. This step simplifies alignment of the new timing set.

Removing the Old Camshaft

With the timing cover off and the timing chain/gears removed (take note of the keyway positions), you can extract the old cam.

Remove the Camshaft

  • Remove the camshaft thrust plate bolts and slide the plate off.
  • Carefully slide the old camshaft out toward the front of the engine. Use a gentle rotating motion to avoid scoring the cam bearings.
  • Inspect the old cam lobes for pitting, flat spots, or excessive wear. This is a good opportunity to examine the lifters and the condition of the oil galleys.

If the old cam shows severe wear, consider replacing the lifters without question. A worn lifter can quickly destroy a new camshaft.

Clean and Inspect the Engine Case

Use a clean rag to wipe down the cam bore and timing cover area. Look for any metal debris or sludge. This is also a good time to check the condition of the cam bearings — if they are scored or loose, they should be replaced before installing the new cam.

Installing the Ram Air III Camshaft

Now the crucial step: installing the new cam. Follow these steps carefully to ensure longevity and optimal performance.

Lubricate and Install the Cam

  • Liberally apply assembly lube to the camshaft journals and lobes. Also apply a generous coat of high‑zinc engine oil to the lifter bores.
  • Slide the Ram Air III camshaft into the engine from the front, rotating it slowly to align with the bearings. Do not force it — if it hangs up, check for obstructions.
  • Once the cam is fully seated, install the thrust plate and torque to specifications (typically 15–20 ft‑lb).

Install the Timing Chain and Gears

  • Place the crankshaft sprocket on the crank keyway. Rotate the crank so that the keyway points to the 12 o’clock position (TDC).
  • Align the camshaft sprocket so that the timing marks on both sprockets are facing each other (or as specified by the chain manufacturer). Most double‑roller sets require the marks to be aligned with the chain slack on the driver side.
  • Install the timing chain and gear set, then torque the cam bolt(s) to 20–30 ft‑lb for single bolt or 15 ft‑lb for three‑bolt pattern.
  • Rotate the engine by hand two full revolutions to verify that the timing marks return to alignment. If they don’t, re‑check your installation.

Using a degree wheel and dial indicator ensures the cam is installed at the correct intake centerline. Even a new cam can be off by a few degrees due to manufacturing tolerances or indexing errors. For the Ram Air III profile, the intake centerline is typically 112° (advance ground in). If your measured centerline deviates, you can use offset cam bushings or change the keyway position to correct it. This guide to degreeing a Pontiac cam explains the process in detail.

Reassembling the Engine

After the new cam and timing set are installed, reassemble the rest of the engine. Attention to detail here prevents leaks and ensures reliable operation.

Install Timing Cover and Water Pump

  • Apply a thin bead of silicone sealant (or a new gasket) to the timing cover. Install the front seal with a seal driver.
  • Torque the timing cover bolts to 15 ft‑lb in a cross‑pattern.
  • Reinstall the harmonic balancer: apply a light coat of oil to the seal surface and tap it on with a balancer installer tool (never hammer it on). Torque the balancer bolt to 160 ft‑lb.
  • Reattach the water pump and tighten bolts to 20 ft‑lb.

Install New Lifters, Pushrods, and Rockers

If you’re using the original rocker arms, inspect the pushrod tips and rocker studs for wear. For a Ram Air III cam, stock 1.5:1 rockers are sufficient — upgrading to 1.65:1 rockers can increase lift but will require checking valve spring clearance. Always use new lifters: after placing them in the bores, apply assembly lube to the pushrod tips and rocker ball surfaces. Adjust the valves to the manufacturer’s spec (typically zero lash plus 1/2 to 3/4 turn for hydraulic lifters).

Reinstall Intake Manifold and Valve Covers

  • Use new intake manifold gaskets and apply a small amount of gasket sealer at the water passages. Torque the intake bolts in sequence to 35 ft‑lb (or per gasket manufacturer’s spec).
  • Reinstall valve covers with new gaskets, tighten gently (over‑tightening warps covers).
  • Reattach the distributor: align the rotor to point at the #1 spark plug terminal (cap removed) before fully seating the distributor. Adjust initial timing after startup.

Fill with Oil and Check for Leaks

Fill the engine with break‑in oil containing high zinc/phosphorus levels. Add a bottle of zinc additive if the oil you choose is API SN or lower. Install a new oil filter. Before starting, pour a small amount of oil over the rocker arms and valve springs to prime the top end. Then crank the engine with the ignition disabled (fuel pump relay off or coil wire disconnected) until the oil pressure gauge registers pressure. This pre‑oils the lifters and cam lobes.

Tuning the Engine

The installation is only half the battle. Proper tuning ensures you realize the full power potential of the Ram Air III cam while maintaining street drivability.

Set Ignition Timing

Start the engine and let it idle at 800–900 rpm. With a timing light, check the initial timing: a good starting point is 12–14° BTDC. Adjust the distributor as needed. Then check total timing at 3,000 rpm: it should be 34–38° BTDC (all in). If the total is too high, reduce the distributor’s mechanical advance travel with an adjustable stop. The Ram Air III cam responds well to a graduated timing curve that comes in fully by 2,800 rpm.

Adjust Carburetor and Idle Mixture

The increased cam duration will reduce manifold vacuum during idle. You may need to adjust the idle speed screw and mixture screws on your carburetor (Quadrajet or aftermarket). Target a smooth idle at 750–850 rpm in gear (for automatic transmissions). If the idle is rough, check for vacuum leaks and ensure the choke is fully open after warm‑up. A vacuum gauge reading of 12–15 in‑Hg is typical for this cam.

Tune Fuel Delivery

The Ram Air III cam’s increased overlap may require richer jetting in the primary and secondary circuits. Start with the stock jetting for a 455 and perform a wide‑open‑throttle plug reading. If the plugs appear white or light gray, increase jet size by 2–4 steps. Also consider upgrading the accelerator pump circuit to prevent hesitation.

Test Drive and Fine‑Tune

Take the car for a short drive. Listen for detonation (pinging) under load — if present, retard timing slightly or use higher‑octane fuel. Check for smooth part‑throttle cruise and good transition to full throttle. Adjust the vacuum advance canister if needed; using a vacuum advance that pulls 10–12° at cruise helps fuel economy and throttle response.

For additional tuning guidance, this Motortrend article on Pontiac 455 tuning offers practical advice. And for a deeper dive into fine‑tuning the Quadrajet, Hemmings’ Quadrajet tuning tips are excellent.

Conclusion

Installing a Ram Air III camshaft in a Pontiac 455 is a rewarding project that delivers a noticeable improvement in power, sound, and driving enjoyment. The process requires careful disassembly, cleanliness, and attention to detail during assembly, but the results are well worth the effort. By following the steps above — from selecting quality parts and correctly timing the cam to dialing in the ignition and carburetion — you’ll transform your 455 into a stronger, more exciting engine that honors Pontiac’s performance heritage. If you’re ever uncertain about a specific step, don’t hesitate to consult with a professional engine builder or experienced Pontiac enthusiast. With the right approach, your 455 will run stronger than ever.