Balmar Pulley Kit, Westerbeke 18, 21A, 27A, 35B, 38B, 42B [48-WSP-18]Pulley Kit, Westerbeke 18, 21A, 27A, 35B, 38B, 42B AltMountSerpentine Pulley Conversion Kit for Westerbeke Diesel Engines Westerbeke Engines Covered: 18, 21A, 27A, 35B, 38B, 42B Kit Includes: Three Ten Groove (J10) Pulleys, Two J10, 40" Circumference Serpentine Belts (one spare) & Mounting Hardware Note: If you specify an AT 200A Alternator, a longer belt length may be required. Replaces: 48 WSP 21A, 48 WSP 27A, 48 WSP 35B, 48 WSP 38B, 48 WSP 42B This