MerCruiser, Crusader Marine (and possibly others) created some of their own 4-bolt 327 marine engines, but none left any Chevrolet engine plant that way; the 4-bolt machining stations in the small-block transfer lines didn't exist at Flint or Tonawanda until the 1968 calendar year.
Another low-volume small-block line existed at Holden's (GM) in Australia; that one may or may not have had 4-bolt machining capability.
