 To a degree, some of these maladies were dealt with during the Zephyr's first year, and Ford improved the engine by adopting hydraulic valve lifters for 1938 and cast-iron heads and oiling improvements for 1942.Yet this V-12 never shed its reputation for service troubles, though the postwar versions were actually quite reliable.The V12 was eventually replaced by the InVincible 8, simply a version of the flathead V8 found on Ford's truck line.