Do you have the need? The need for speed? Meet RAD’s Chop Gun DIY Full Build Kit.

Chop Gun — RAD DIY Full Build Kit

Transform your 6.2L into a RAD Chop Gun engine!

Starting at $4,999

Already have a solid 6.2L LS? Chop Gun brings together the cam, supporting valvetrain, fuel system, oiling components, engine management, and RAD tune to give it a new personality. It has the chop and throttle response you came for, backed by a matched combination of parts instead of a pile of separate purchases.

This is also a chance to take care of an engine whose history you may not know. The kit includes new lifters, a full top-end gasket and seal package, head bolts, selected sensors, and other components worth addressing while the engine is apart. Engines with factory DoD get the parts needed to remove it as part of the build.

The package covers four major jobs:

• Give it Chop Gun character. The RAD-specified camshaft is paired with the springs, pushrods, lifters, timing components, and fueling selected for the combination.
• Refresh the top end. New head gaskets, valve-stem seals, head bolts, lifters, and upper-engine seals make the required head removal an opportunity to service the engine properly.
• Update the oiling system. A new standard-volume, standard-pressure oil pump and complete rear-sump pan package provide a fresh, matched foundation for the build.
• Make it run as one package. A standalone ECU, Gen IV LS engine harness, electronic-throttle connections, sensors, and RAD tune bring the mechanical and electronic pieces together.

You supply a mechanically sound 6.2L engine and do the work yourself or with your chosen shop. RAD supplies the matched parts and calibration to build your own Chop Gun.

What’s Included in the Chop Gun Build Kit

Camshaft, Valvetrain & DoD Elimination

• RAD-specified Chop Gun camshaft
• New camshaft mounting bolts
• Camshaft retainer and bolt kit
• New performance timing set
• Timing-chain damper
• New hydraulic roller lifters
• New lifter guide trays
• Valve-spring kit matched to the camshaft
• Matched pushrods
• Non-VVT front timing cover with cam-position sensor, wiring, gasket, and installation hardware
• Replacement valley cover for engines equipped with DoD

Cylinder-head removal is required to install the new lifters and guide trays. If your engine has DoD, the included components allow its factory lifter hardware to be removed during that work.

Cylinder-Head & Top-End Service

• Complete top-end gasket and seal kit, including new head gaskets and valve-stem seals
• Valve-cover gaskets and other upper-engine seals supplied with the top-end kit
• New cylinder-head bolts for reassembly
• RAD-logo valve covers with ignition-coil mounting provisions
• New valve-cover mounting bolts

The kit reuses your serviceable stock cylinder heads. Head machining, replacement heads, and short-block rebuilding are not part of the base package.

Oiling & Rear-Sump Pan Package

• New standard-volume, standard-pressure oil pump
  
• Rear-sump oil pan with oil-filter mounting provision
• Pickup matched to the supplied pan
• Oil-pan gasket and installation hardware
• Oil dipstick
• Engine oil and oil filter for customer installation

The rear-sump pan is the standard configuration. If your chassis calls for a front-sump or another pan arrangement, contact RAD before ordering so the oiling package can be specified for your build.

Fuel & Ignition Service

• Fuel rails
• Matched set of fuel injectors
• Two sets of spark plugs

ECU, Engine Harness & Sensors

• Standalone engine ECU with support for the OEM LS3 electronic throttle
• Terminated Gen IV LS engine harness
• Electronic-throttle and accelerator-pedal adapter harnesses
• Injector, alternator, and applicable sensor adapter harnesses supplied with the ECU package
• Manual-transmission speed-sensor harness supplied with the ECU package
• Wideband oxygen sensor and installation fitting
• Intake-air-temperature sensor and installation fitting
• Flex-fuel sensor
• New crank-position sensor
• MAP sensor
• Engine coolant-temperature sensor
• Fuel-pressure sensor
• Oil-pressure sensor
• Oil-temperature sensor

RAD Chop Gun Tune

The included ECU receives a RAD Chop Gun calibration developed for the supplied camshaft, injectors, sensors, and engine-management package. It covers startup, idle, throttle response, normal driving, flex-fuel operation, and full-throttle performance. The installer should verify the completed installation and calibration in the vehicle before driving.

The customer’s sound 6.2L block, rotating assembly, cylinder heads, intake manifold, throttle body, rocker arms, ignition components, and compatible accessories provide the starting point for the build.

Starting Engine and Vehicle Requirements

The standard Chop Gun DIY Full Build Kit is specified around a sound, largely stock Gen IV 6.2L LS. Before ordering, the following are assumed:

• A complete, serviceable Gen IV 6.2L engine core. The block, crankshaft, connecting rods, pistons, rocker arms, ignition coils, and other reused components must be suitable for continued service. Engines with or without VVT and/or DoD are acceptable. Tell RAD which systems your engine has so the correct conversion components are supplied.
• Good underlying engine condition. Check compression, leakdown, and oil pressure before disassembly where possible. The core must be free of material defects, including damaged cylinder walls, bearing damage, cracks, overheating damage, and oil or coolant contamination. Machine work and short-block repairs are not included.
• Stock, unmodified OEM rectangular-port cylinder heads, typically 821 or 823 castings. The heads must not have been milled, ported, or otherwise altered, and their decks, valves, and guides must be serviceable.
• An OEM LS3 car-style intake manifold and OEM LS3 electronic throttle body. Both are assumed to be supplied with your engine or sourced separately.
• A compatible electronic accelerator pedal and vehicle-side systems. The ECU package includes the specified pedal adapter harness, but the pedal and the vehicle’s fuel supply, cooling, exhaust, charging, starting, and other installation systems must be compatible and supplied separately as needed.
• Room for the included rear-sump oil pan. Confirm chassis, crossmember, steering, and ground-clearance requirements before ordering. Other pan configurations can be discussed with RAD.
• An installer equipped for head-off engine work. Installation includes removing the cylinder heads, changing the camshaft and lifters, fitting the valve springs and oiling components, and checking clearances and operation before startup.

Have a different combination? Contact RAD before ordering if your engine, heads, intake, throttle body, pedal, or vehicle installation differs from these assumptions. RAD can accommodate many configurations once the starting point is clear.

The Parts Behind the RAD Badge

Typical component brands across RAD packages include BTR, Texas Speed, Cam Motion, AFR, PRC, Mahle, ARP, GM Performance, Engine Pro, Fuel Injector Clinic, Bosch, Haltech, and MaxxECU. For turbo systems, that roster also includes Garrett, BorgWarner, and Turbosmart. RAD favors American-made performance hardware and proven specialists throughout each combination. Every part is selected for quality, durability, and fit, so you can have confidence in both the components and the RAD engineering behind them.