Performance Rebuild

4.8 LS performance recipe guide.

Use this page to plan a 4.8 LS around common 400, 500, and 600 horsepower recipe ideas. The 4.8 can make impressive power, but it usually needs RPM, airflow, boost, nitrous, or a very well-matched combination to reach the bigger numbers.

Read Before Buying

Horsepower recipes are not guarantees.

These horsepower levels are based on dyno-tested LS recipe information and should be treated as planning targets. Dyno numbers depend on the exact engine, compression, camshaft, heads, intake, exhaust, fuel, tuning, and dyno setup.

Many published LS recipe numbers are engine dyno or flywheel-style numbers. Rear-wheel horsepower can easily be 100 to 150 horsepower lower after drivetrain loss, converter loss, accessory load, tire size, and vehicle setup.

Once a stock-bottom-end LS build gets past roughly 500 horsepower, reliability becomes much less forgiving and the engine can turn into what builders call a ticking time bomb if the foundation is ignored. Above 600 horsepower, the upgrades should extend past bearings and include careful machine-shop measurements, piston ring gap, stronger rods and pistons, crank inspection or upgrade planning, fuel system support, and professional tuning.

Horsepower Combination Planner

Choose the horsepower target before choosing parts.

Use these wide boxes as the working spots for each horsepower combination. Each level can hold the exact parts list for that power goal as the combo gets filled in.

400 HP Target

4.8 Crane cam and spring recipe

A 4.8 LS paired with this Crane camshaft and matching valve springs made slightly above the 400 horsepower mark at the flywheel in the referenced dyno combination.

Crane cam link

500 HP Target

4.8 Crane cam and cylinder head combo

For the 500 horsepower 4.8 recipe, keep the same Crane camshaft foundation from the 400 horsepower build and add real cylinder head airflow. Ported 706 heads are commonly sourced from 5.3 LS engines and can work well after porting, while the Trick Flow GenX 205 heads are the linked aftermarket head option.

Crane cam link Trick Flow heads link LSXrt intake link

600 HP Target

4.8 turbo cam and boost combo

The 600 horsepower 4.8 recipe used a turbo setup with a Stage 2 BTR turbo cam, PAC 1219 springs, and 706 heads from a 5.3. Trick Flow GenX 205 heads and an LSXrt intake can also fit this airflow path. Without the turbo the engine made 409 horsepower, then made about 600 horsepower on only 8.5 pounds of boost. More boost can make more power, but at this point stock internals are already being pushed beyond a safe long-term limit.

BTR Stage 2 turbo cam link PAC 1219 springs link Trick Flow heads link LSXrt intake link

Reliability Support

Do not chase power on a worn-out foundation.

These support paths help keep the engine from becoming a short-lived power test. Start with refresh parts, then add stronger bottom-end and valvetrain parts as the horsepower goal rises.

Foundation

Stock refresh kit

Use this before adding power when the engine is mostly stock and needs normal wear parts, gaskets, seals, and basic rebuild planning.

Open stock refresh kit

500+ Support

Bearings, oiling, and valvetrain insurance

For harder-use builds, plan bearings, oil pump, lifters, trunnions, pushrods, springs, head hardware, and accurate measurements.

Choose support parts

600+ Support

Rotating assembly planning

For 600 horsepower planning, look beyond bearings and include pistons, rods, ring gap, crank inspection, machine work, fuel system, and tuning.

View rotating assembly parts

Our Promise

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Champ Motorsports is built around dependable parts, clear LS fitment guidance, and fair pricing. Every recommendation is organized to make LS engine building easier to plan and easier to order correctly.

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