has anyone used this gear drive?

Buddy has one on a 351C, same setup and I built a 451 with same part. You set timing with either a bushing for big moves, and the multi key bottom gear for small moves. You set clearance with a piece of newspaper on a single idler ,If the gears turn blue they are too close! The floater does not have this issue as the idlers rock back and forth just a hair, setting their own clearance. Never had a torrington come apart on one of these, but did have a rocker bearing fail. Single idler had a torrington, the dual idler had a bronze bushing. They are not for everyone, once you have one, you usually get a good chain on your next build as the noise is distracting.