Chevrolet LSX -20 AN Chrome Aluminum Water Pump Adapter Kit

• -20 AN adapter converts the LS water pump outlet to AN-style hose fittings

• 160° opening rating supports high-flow coolant circulation for performance builds

• Fits Chevrolet Gen III/IV LS small block V8s — 4.8L through 6.2L

• Chrome aluminum construction with O-ring seal for a clean, durable connection

This water pump adapter kit converts the LS water pump outlet to -20 AN hose fittings, giving custom cooling system builds a high-flow connection point for AN-style plumbing instead of standard hose routing. Chrome-finished aluminum construction and an included O-ring seal support a durable, leak-resistant connection with a 160° opening rating for high-flow coolant circulation.

This kit is built for Chevrolet Gen III/IV LS small block V8 engines that use a separate thermostat and water neck housing — 4.8L (LR4, LY2), 5.3L (LM7, L59, LM4, L33, LC9, LH6, LY5, LMG), 5.7L (LS1, LS6), 6.0L (LQ4, LQ9, LS2, LY6, L76, L96), and 6.2L (LS3, L92, L99, LSA, L9H, L94). It is not compatible with Chevy Gen I small block or big block engines, or LT-generation (Gen V) engines, which use different water pump outlet configurations.

An O-ring seal and mounting hardware are included; a thermostat is not included.

Engine Applications
Fits GM LS Gen III/IV small block V8s across the common displacement range — 4.8L, 5.3L, 5.7L, 6.0L, and 6.2L — covering engine codes from the LR4 and LY2 through the LS3, L92, L99, LSA, L9H, and L94. This adapter is specifically for LS engines using a separate thermostat and water neck housing design; commonly used in Silverado, Sierra, Tahoe, Suburban, Yukon, Camaro, Corvette, and LS-equipped GTO/G8 applications.

Installation
Confirm your water pump uses the standard 2.970" bolt hole spacing before ordering. The included O-ring seals at the water pump connection point; a thermostat is not included and should be sourced separately if needed for your build.

What engines does this adapter fit?
GM LS Gen III/IV small block V8 engines from 4.8L through 6.2L, including the LR4, LY2, LM7, L59, LM4, L33, LC9, LH6, LY5, LMG, LS1, LS6, LQ4, LQ9, LS2, LY6, L76, L96, LS3, L92, L99, LSA, L9H, and L94 engine codes.

Does this fit any LS engine, or only certain configurations?
This adapter fits LS engines that use a separate thermostat and water neck housing design — confirm your engine's housing configuration before ordering, since not all LS setups are arranged this way.

Does this fit LT1 or LT4 (Gen V) engines?
No. This kit is built for the LS (Gen III/IV) water pump outlet configuration and is not compatible with LT-generation (Gen V) engines, which use a different design.

Does this include a thermostat?
No. A thermostat is not included and should be sourced separately.

What's the opening temperature rating?
160°.

What hose size does this adapter use?
This kit converts the water pump outlet to -20 AN, matching -20 AN hose and fittings for custom cooling plumbing.

Is this a good option for an LS swap into a non-GM vehicle?
Yes. It's commonly used in LS swap projects where a custom cooling system with AN plumbing is being built from scratch.