How to LS swap: step-by-step overview
The big pieces of every LS swap, in the order you'll deal with them:
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- Choose the engine and know its details: RPO code, 24x or 58x crank reluctor, cable or drive-by-wire throttle, and AFM (Gen IV). These decide the ECU, harness and cam options.
- Mounts: adapters convert the LS to classic three-bolt Chevy mounts, or use chassis-specific swap mounts. Offsets set the engine's fore/aft position.
- Oil pan: junkyard pans often hang too low. Use a swap pan that clears your crossmember (or front axle on 4WD).
- Transmission: the LS keeps 5 of 6 SBC bellhousing bolts and the dowels, but the crank sits farther forward. Old GM autos need a dished flexplate and converter sleeve (except the 1999–2000 LQ4: flat flexplate). Manuals need an LS bellhousing.
- Accessory drive: factory truck drives often hit frame rails. Match the water pump and crank pulley spacing (Corvette, F-body or truck).
- Headers/exhaust: LS-specific swap headers or manifolds for your chassis.
- Cooling: passenger-side radiator ports and a steam line.
- Fuel: 58 psi EFI pump, filter/regulator, and proper AN or EFI-rated lines.
- Engine management: a stock ECU with a standalone harness and tune (VATS off), or a Holley/FiTech system. You can even run a carburetor with a carb intake and MSD ignition box.
- Driveline: new driveshaft length and yokes; check driveline angles (about 2° down at the trans, 2° up at the pinion).
See our per-vehicle guides for exact parts and prices.
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