L83/L86 Cam Swap Parts List

For an L83 or L86, I’d start with either Brian Tooley Racing or Gwatney Performance Innovations. Both offer configurable packages, and what’s included depends on the options you select, so go through every dropdown before ordering.

I’m not going to call one cam the best choice for every truck. Vehicle weight, converter, gearing, power adder, intended rpm range and how you actually use the truck all matter. One of the established off-the-shelf grinds will probably work great. Most people don’t need a custom-cut cam.

Replacing the AFM lifters means removing the cylinder heads. A typical delete requires:

• Sixteen non-AFM lifters
• Four lifter trays
• AFM oil-passage plugs or an appropriate replacement valley cover
• Head gaskets
• New torque-to-yield head bolts or reusable head studs
• AFM disabled in the calibration

Some packages include all of it. Others let you add each part individually. With the heads already off, inspect the valve guides, seals, rocker trunnions and the rest of the valvetrain instead of blindly putting everything back together.

Having a local machine shop disassemble, clean, inspect and reassemble the heads with the new parts is also a good option. It may be cheaper than you think if you don’t already own the tools.

The supporting-part and tool links below include Amazon affiliate links. As an Amazon Associate I earn from qualifying purchases.

The correct VVT setup depends on the cam. That may mean a limiter, lockout or complete delete. Confirm that you have:

• The VVT hardware recommended for the cam
• A new phaser bolt when a factory-style phaser is retained
• The correct cam retainer plate, gasket and hardware
• A timing-chain tensioner or guide if the original is being replaced
• The matching calibration changes

A limiter, lockout and delete are not interchangeable just because they appear beside one another on an order page. Many packages call for either a 4-degree limiter or a zero-degree lockout/delete. Use the exact setup listed for the cam.

Installation position and chain-indexing details are covered in the Gen V cam timing reference →

A package may include pushrods, but I would still verify the required length on the assembled engine. Cam base circle, lifter design, head milling, gasket thickness, valve work and normal production tolerances can all change the answer.

The correct pushrod is the one that produces the intended preload in your engine. Don’t order a length just because someone with a similar truck used it.

Establish zero lash, measure the checker and use the Gen V Garage pushrod-length and lifter-preload calculator →

The cam’s fuel-pump lobe, base circle and the installed high-pressure pump all affect pump geometry. Depending on the combination, a lash cap may be required. Another combination may specifically require that one not be used.

Verify:

• The cam manufacturer’s recommendation and fuel-pump lobe specification
• The installed HPFP and follower
• Whether a lash cap is required
• Preload at minimum fuel-lobe lift
• Remaining pump travel at maximum lift

The complete procedure is in the Gen V HPFP lash and available-travel guide →

Don’t assume piston-to-valve clearance is safe because someone else ran the same advertised cam. Clearance changes with cam timing, phaser movement, piston design, head milling, gasket thickness, valve work and actual short-block dimensions.

If the combination falls outside what the cam supplier has confirmed, measure it. This matters even more with milled heads, thinner gaskets, larger cams, altered cam timing or a short block that is no longer stock.

This is the group most likely to leave the truck sitting apart while you wait for one missing part. Check for:

• Head gaskets
• New head bolts or studs
• Intake-manifold gaskets
• Exhaust-manifold or header gaskets
• Valve-cover gaskets
• Water-pump housing gaskets
• Front crankshaft seal
• HPFP gasket
• Cam retainer plate and gasket
• New phaser bolt where applicable
• New application-correct crankshaft balancer bolt
• Oil-pickup-tube seal
• RTV for the front-cover and oil-pan joints
• Any additional oil-pan seals disturbed during the job

The intake and valve-cover gaskets can normally be reused if they remain undamaged and in good condition. Inspect them before deciding they’re going back on.

Don’t automatically coat every bolt in sealant. Use it only on the holes and fasteners that require it, and follow the product or service instructions.

• An inch-pound torque wrench for the smaller covers and fasteners
• A foot-pound torque wrench for the larger fasteners
• A torque-angle wrench or separate angle gauge
• A harmonic-balancer puller and the correct installation setup
• A Gen V valve-spring compressor
• An adjustable pushrod checker and caliper long enough to measure it
• Feeler gauges and a dial indicator where required
• Piston-to-valve checking equipment if clearance must be measured
• An oil-pump alignment tool
• Fuel-line disconnect tools
• A scan tool or tuning interface
• The correct torque specifications and tightening sequences

Bolt order and staged tightening information are in the Gen V Garage tightening-sequence reference →

• Engine oil and filter
• Coolant
• Assembly lubricant
• Brake cleaner
• Correct RTV
• Threadlocker or sealant where specified
• Shop towels
• Fresh spark plugs if they’re due
• Plug wires if they’re being replaced
• O₂-sensor extensions if adding long-tube headers

Use the sealant and thread treatment specified for the part. More isn’t better.

Not every cam requires a converter, but choosing a cam without considering the converter is an easy way to make a heavy truck miserable to drive. Vehicle weight, gearing, tire diameter, transmission, powerband and how the truck is used all matter.

I’ve been happy with the billet triple-disc Circle D converter in my truck. They’re good at helping spec the right converter for the combination. It also doesn’t hurt to involve whoever is tuning it before ordering the cam or converter.

If the cam requires a converter, treat it as part of the combination instead of something to figure out afterward. Otherwise, you may be dropping the transmission or pulling the engine again and doing the labor twice.

Depending on the build, the calibration may need changes to:

• AFM/DOD
• VVT control
• Idle airflow and speed
• Fueling
• Spark
• Torque modeling
• HPFP and fuel-lobe settings
• Converter and transmission behavior

Finishing the mechanical work and then trying to find someone willing to tune it is backwards. Have the plan handled before the first startup. A Gen V torque-based ECM is not a great place to learn by guessing.