Am almost certain, no. BOPC all had differing flexplates/flywheels as the ring gear counts, diameters, and probably weights and bolt circles were not the same.
In case you need a Buick flexplate,I have about half a dozen of them .A couple are just as good as new .Bruno.
Among the differences would be the crankshaft bolt pattern, and the fact that the 396 flywheel is neutral-balanced, where the BBB flywheel will have deliberate offset weight (via drilling the opposite side) to assist in engine balance. The BBB flywheel is match-balanced to the engine; ideally you'd have the replacement balanced to the same spec as the original flywheel that came with the engine. Nobody does, though. [Edited to remove "flexplate" and replace with "flywheel".]
The only similaritys are that when bolted to a Crank they spin, they house a pilot bushing and the pressure plate bolts to them..
