The Elite Series 400 Amp Alternator is engineered to deliver exceptional amperage output and reliability. Featuring 6-phase technology and dual rectifier assemblies with 12 robust diodes, this alternator is designed for daily use and high performance. It produces over 200 amps at engine idle and exceeds 400 amps at cruising speeds (HOT RATED). This model includes a smaller diameter pulley, which typically requires a shorter belt (1/2 inch to 1 inch shorter than the original) for optimal belt tension. Installation Notes: For vehicles originally equipped with the CS144 heavy-duty charging system, an additional rectangle-to-oval adapter harness may be required (less common scenario). This alternator is a direct plug-in replacement for trucks equipped with the standard oval-shaped 4-pin plug, as depicted. BSTOCK