[poncho-mike]

Dealerships were pretty lax on the requirements for destroying blocks replaced under warranty.

Around 1984, I ran into a guy who was employed by a Pontiac dealership in the Charlotte NC area from about 1965 to 1974. He had a 1963 Catalina with a 1967 428HO with a 66 tripower setup. He also had five or six 4-bolt 400s, 428s and 455s that were replaced by the dealership he worked at. A couple of the blocks had repairable damage, such as a crack in a cylinder wall, while there appeared to be nothing wrong with the rest. The undamaged blocks were bare, so they probably had spun rod bearings.

This guy was close to his service manager, since they both bracket raced. His service manager retired and downsized a few years later, and I acquired an additional 5 or 6 4-bolt blocks he had stashed.