Even if a SBC balancer in general was a good replacement for the the inline 6 engines, I would find something other than a Rattler to use.
I saw and helped make the very first prototype of one that was made. TCI used our shop as the source to do this back in the late 80's. It looked cool and innovative for the time, but after they went into production, I saw quite a few come through our shop that were built by other builders and racers, and you literally had to destroy them to get them off of the cranks. Because of the rattling action inside of them, they would weld themselves to the crank snout. On one BBC, I saw our teardown guy actually have to take a cutoff wheel and a sawzall and cut it apart to access the hub and cut it off to remove it. For those experiences i've had with them, I would never use one.
