i john,
All the Veco .45's I ever knew about are BB. Bearings are available. As far as the engine being used for stunt, Bob Palmer used them in his "Skyscraper", Bob Gialdini used one in his "Eclipse", and IIRC, Lew McFarland switched from the K&B .45 to the Veco .45 in his famous "Shark". There were others who used the Veco .45 during the transition from .35 size to "bigger" planes in the mid '60's. Billy Werwage talks about them in regards to when he was using the K&B .45, but felt they were too heavy. Weight was a concern but can be worked around for most of us, no problem.
The Veco .50 is the same case, etc., except it uses a Dykes ring.
Big Bear