The 504-0200C3 (often listed as 0200.C3 or AMC 910057) is a new aluminum alloy cylinder head designed for Peugeot 504 and 505 models with 1.8L or 2.0L XN1/XN1P engines. These aftermarket, performance-oriented heads are designed for durability, often featuring updated materials to improve airflow and combustion efficiency.