AV&V valve seats are made from a highly alloyed material and are easy to machine with cutter and stone. They are radiused for easier installation, resist severe pounding, dissipate heat better than most other valve seats on the market and are suitable for both leaded and unleaded fuel. They harden in use during running in the engine. Available for a limited number of models as a direct-install or pick the size from one of the tables below. Sold each.