Spartan MLS Head Gasket AMC 390-401 4.250 x .039

The Spartan MLS Head Gasket AMC 390-401 4.250 x .039 from SCE Gaskets is purpose-built for restorers and performance builders working with classic AMC muscle cars and industrial engines. This gasket is specifically designed for the AMC 390 and 401 cubic-inch blocks, ensuring a reliable seal for those undertaking rebuilds of models like the Javelin, AMX, or Hornet.

MLS (Multi-Layer Steel) head gaskets represent the evolution beyond old-school composite designs, offering superior durability and thermal stability for both stock and modified applications. SCE's Spartan MLS gasket uses multiple hardened steel layers bonded with specialized elastomers to maintain a consistent seal across the full combustion cycle. The 4.250-inch bore sizing and 0.039-inch thickness are precision-engineered to match AMC 390-401 block and cylinder head specifications, ensuring proper clamping load distribution without over-compression or hot-spot erosion.

This gasket is ideal for frame-off restorations and performance builds targeting compression ratios between 8.5:1 and 11:1. Its construction resists blow-by and reduces coolant seepage, maintaining pressure integrity even under higher boost or compression ratios. The gasket's facing also resists corrosion from ethanol fuels and modern coolant chemistry, making it a reliable choice for both period-correct and modernized cooling systems.