Cam Phasing

Here are a couple of good examples. NON of the small journal small block Chevy engines had balancer bolts. They weren't even drilled from the factory. That INCLUDES ALL of the 283 HP engines and the 365HP and 375HP 327 engines AS WELL AS the DZ302. Most all slant six engines, although drilled for balancer bolts, had none. What was bearing the loads on all those examples?