The 216s had poured babbitt instead of shell type insert bearings. The '54 235 began the "full pressure" (oil pressure to the rods, the crank always had it) and insert rod and crank bearings. I believe the main thing was easier service and rebuilding. The old system actually works very well for any years. The 261 captain bar are on the side of the block and would not be seen in those pictures.
Captain Bars
