Best LS swap radiator
An LS needs a radiator plumbed differently from an old small block:
- Both hoses are on the passenger side. Most LS water pumps have the inlet and outlet on the passenger side, so LS-swap radiators put both ports on the passenger-side tank.
- You need a steam port. The thermostat sits low on the water pump, so air gets trapped. A steam line purges it, and most LS-swap radiators include a port for it.
- Hose size: Speedway says the upper hose is 1-1/4 in; ICT Billet lists 1-3/8 in at the pump. Check your pump and radiator before buying hoses.
Options:
- Direct-fit LS radiator (e.g., DeWitts for C10 or Chevelle, about $1,700–1,800). Bolts in and looks factory.
- Budget: a universal double-pass radiator plus an LS radiator/hose adapter with a steam port (the Speedway adapter is about $43).
- Keep your factory V8 radiator if it's healthy (not an original V6 unit) and add a steam-port hose adapter.
Pair it with electric fans and a shroud, or a mechanical fan (on trucks, that needs a Gen III Vortec water pump, shroud and fan clutch).
Related questions
- LS steam vent: do I need it?
- What causes P0327 or P0332 knock sensor codes on a Gen 3 LS?
- Where do the knock sensors go on a 6.0L iron block?
Sources
- LS Cooling & Water Pump swap guide — ICT Billet
- Squarebody LS Swap Guide | 73-87 C10 Parts List — Speedway Motors
- Squarebody LS Swap Guide | 73-87 K10 Parts List — Speedway Motors
- LS Swap How-To Guide — Speedway Motors