An LS swap into a full-size Chevy or GMC truck is not a single parts list — it is a project that runs from donor identification all the way to first start and road testing. This checklist walks you through all 22 build phases, plus parts, budget and troubleshooting worksheets, as a printable PDF you can take into the shop and an interactive tool you can work through on your phone.
One rule governs everything here. Physical engine generation, electronics generation, controller family and exact controller application, crank/cam signal, throttle system, VVT, AFM/DOD, transmission control and your destination chassis (2WD/4WD) are separate attributes. Do not classify compatibility as “Gen III” or “Gen IV” alone. This checklist organizes your project and flags the required checks; it does not verify compatibility for you — factory service information and the instructions that came with your parts govern.
Download the printable checklist
Printable, mostly black-and-white, and built to write on in the shop.
- Full checklist (PDF, US Letter) — all 22 phases and worksheets.
- One-page quick reference (PDF) — the 12 project gates for the shop wall.
- Full checklist (PDF, A4)
- Editable version (Word .docx)
Download the full checklist (PDF)
Use the interactive checklist
Work through the checklist on your phone or desktop — it tracks your progress, saves to your browser, filters by your build (Gen III/IV, DBC/DBW, automatic/manual, 2WD/4WD) and prints cleanly. Open the interactive LS swap checklist →
The 12 project gates
Every LS swap passes through these milestones in order. The full checklist expands each one into detailed verification steps.
- Identify the truck
- Identify the engine
- Match engine and electronics
- Select transmission
- Confirm mechanical fitment
- Build fuel system
- Build cooling system
- Complete wiring
- Complete calibration
- Pre-start inspection
- First start
- Road-test inspection
What’s inside: the 22 build phases
- Phase 1 — Define the Project — gate: Identify the truck
- Phase 2 — Identify the Donor Engine — gate: Identify the engine
- Phase 3 — Engine Condition Inspection
- Phase 4 — Match the Engine Electronics — gate: Match engine and electronics
- Phase 5 — Select the Transmission & Transfer Case — gate: Select transmission
- Phase 6 — Engine Mounting & Chassis Fitment — gate: Confirm mechanical fitment
- Phase 7 — Accessory Drive
- Phase 8 — Fuel System — gate: Build fuel system
- Phase 9 — Cooling System — gate: Build cooling system
- Phase 10 — Exhaust System
- Phase 11 — Wiring & Power Distribution — gate: Complete wiring
- Phase 12 — Gauges & Driver Controls
- Phase 13 — Air Conditioning & Heater
- Phase 14 — Calibration & Programming — gate: Complete calibration
- Phase 15 — Pre-Start Inspection — gate: Pre-start inspection
- Phase 16 — Oil-System Priming
- Phase 17 — First Start — gate: First start
- Phase 18 — Initial Heat Cycle
- Phase 19 — Stationary Drivetrain Test
- Phase 20 — First Road Test — gate: Road-test inspection
- Phase 21 — Post-Road-Test Inspection
- Phase 22 — Final Completion Checklist
Plus a high-risk inspection-gate sign-off sheet, a grouped parts inventory worksheet, a budget worksheet, and blank troubleshooting worksheets for 19 common symptoms.
Frequently asked questions
Does every LS swap need a custom tune?
Most production-donor swaps need calibration work, but “every LS swap needs a tune, no exceptions” is an overstatement. A correctly matched, pre-calibrated Chevrolet Performance control package or a pre-configured aftermarket controller can arrive programmed for its specified hardware. Separate four things: initial calibration, configuration, emissions readiness, and optional custom tuning.
My donor is drive-by-wire but I want a cable pedal — is that just a “DBW delete” tune?
No. Going from drive-by-wire (DBW) to drive-by-cable (DBC) is a hardware, controller, wiring and calibration conversion. It requires a cable throttle body, idle-air-control hardware, a compatible throttle-position sensor, a compatible intake and the matching controller strategy. A tune cannot replace missing hardware.
Is Gen IV always a 58x crank with front cam sensing?
No. The generation boundary is architectural, not a feature checklist. Early Gen IV packages can use a 24x crank and 1x cam signal with an E40 controller, while later versions use 58x/4x with E38 or E67. The 2005 Corvette LS2 uses 24x/1x with E40 and the 2006 uses 58x/4x with E38. Record crank reluctor, cam signal, throttle type and controller as separate fields.
What oil pan do I need for a Squarebody or OBS LS swap?
There is no universal answer, and “front-sump vs rear-sump” shorthand is not enough. Oil-pan choice must be based on your measured chassis, crossmember, steering-linkage, engine-position, stroke, pickup, windage-tray and (on 4WD) front-differential clearance. Note that the popular Holley 302-2 GM LS swap pan is a rear-sump pan, and the manufacturer excludes the LS7 and cranks with stroke over 3.62 inches.
If a transmission bolts to the engine, is it compatible?
Bolting up is not complete compatibility. Confirm mechanical fit (flexplate/flywheel, converter/pilot depth, crank-flange depth), electronic control strategy (internal vs external TCM, network), calibration (gear ratio, tire size, segment) and torque suitability separately.
How do I identify my donor LS engine correctly?
An intake cover, a seller’s description or an advertised displacement is not enough. Confirm the RPO from donor documentation, record the VIN, and photograph the engine assembly stamp and block and head castings. Displacement is RPO-specific: LR4 is 4.8 L, LM7 is 5.3 L, and the LC9 is a 5.3 L Gen IV engine, not a 4.8.
Related LS swap guides
Disclaimer
- This checklist is an educational planning aid.
- Vehicle combinations vary; do not assume one combination applies to every truck.
- Factory service information and component-manufacturer instructions govern.
- Builders must verify exact year, RPO, controller, transmission and chassis.
- Fuel, electrical, braking and drivetrain work can create severe hazards if performed incorrectly.
- Roadworthiness, emissions and inspection laws vary by jurisdiction.
- Professional inspection is recommended before road use.
The Complete LS Swap Checklist for Chevy & GMC Trucks · FullSizeChevy.com · Version 1.0 · Revised 2026-08-01.