--- Rebuilt Upgraded GM 604 Tech Bulletin --- Date: 2/3/2026 Bulletin #: 2026-1 Sealed Engine Alliance Leaders announced the following aftermarket items have been approved as replacement parts on rebuilt upgraded GM 88958604 / 88869604 Engines for all Sealed Engine Alliance series and tracks. Approved Aftermarket Replacement Crankshafts – Scat 4-350-3480-5700-L & Liberty ZR-3500-L4340 353340 Approved Aftermarket Crank Hub – Allstar Performance ALL90030 ***Stock GM 604 Reminde