BBM To TH400 Ultra-Bell

The BBM to TH400 Ultra-Bell is a premium aluminum bellhousing designed for Mopar B and RB-series engines paired with TH400 transmissions. This SFI 30.1-certified bellhousing bridges the gap between big-block Chrysler engine families and one of the most durable automatic transmissions in high-performance applications. Built from lightweight aluminum in natural finish, the Ultra-Bell combines structural integrity with reduced rotating mass—a critical advantage in drag racing, street performance, and engine swaps where weight savings directly improve acceleration and handling balance.

SFI 30.1 certification confirms this bellhousing meets safety standards for high-performance engine combinations, ensuring proper containment during catastrophic failure scenarios. The aluminum construction offers a significant weight reduction compared to iron alternatives while maintaining the rigidity required for TH400 mounting. At 25.45 lbs, the Ultra-Bell minimizes overall drivetrain mass without compromising durability. The natural aluminum finish provides a clean appearance and allows for custom finishing if desired.

This bellhousing serves builders and restorers performing modern TH400 conversions on classic Mopar B and RB-powered vehicles, as well as those constructing high-output engines for competition. The BBM to TH400 Ultra-Bell is essential for anyone standardizing on the TH400's proven strength and wide aftermarket support while preserving original engine platform authenticity or upgrading from weaker factory transmissions. Compatibility with both B-series (318, 340, 360) and RB-series (383, 400, 426, 440) blocks makes this a versatile solution for Mopar enthusiasts.