Tech Bulletin 26-001

--- 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 Reminder***

To receive any weight break offered by a track or series unaltered GM 88958604 / 88869604 engines must remain as produced by GM. The only approved modification permitted to the engine is the oil pan can be changed to a Champ Pan Part #CP106LTRB. The pan must be replaced and sealed by a certified S.E.A.L. builder. All other parts including valve springs & balancer must remain with the OEM parts as produced and sold by GM.

If you have any questions, please reach out to your respective series or engine builder for more information.