Flexplate CM Steel SFI Mopar SB/BB 6-Bolt

The PRW Industries Flexplate CM Steel SFI Mopar SB/BB 6-Bolt is a precision-engineered flexplate designed for Mopar B-series and RB-series engine blocks requiring internal balance configuration. This chromoly steel flexplate meets SFI 29.1 certification standards, ensuring structural integrity and safety under high-load engine applications where traditional cast iron flexplates fall short in durability and performance consistency.

Weighing 4.7 pounds and dimensioned at 13.2 x 0.7 x 13.3 inches, this flexplate delivers the internal balance specification critical for engine builds where rotating assembly weight distribution has been optimized for RPM capability and driveline smoothness. The six-bolt pattern ensures secure attachment to the crankshaft flange, while chromoly material provides superior fatigue resistance compared to standard cast designs. The SFI 29.1 rating confirms this component meets sanctioning body requirements for high-performance and racing applications where component failure carries risk.

This flexplate is engineered for engine builders, performance shops, and serious enthusiasts constructing or rebuilding Mopar B or RB engines destined for bracket racing, street performance, or engine swap applications. The internal balance specification demands precise matching with the engine's rotating assembly—balancing must be verified during installation to prevent driveline vibration and premature transmission wear. Buyers should confirm their specific engine block series and balance type before ordering to ensure proper fitment with existing crankshaft and torque converter assemblies.

Mopar B and RB series blocks remain popular in classic muscle car restorations, drag racing programs, and engine swaps into non-original platforms. The SFI certification provides documentation of compliance for competition use, while the chromoly construction delivers the reliability demanded in repeated high-RPM duty cycles. PRW Industries' flexplate line focuses on OEM-specification fitment paired with material upgrades—this component maintains factory bolt patterns while upgrading material science to handle modern power levels.