Best LS swap radiator

An LS needs a radiator plumbed differently from an old small block:

Last updated October 10, 2026

• 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: published figures differ: 1-1/4 in for the upper hose vs 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).