Chevy didn't make a 327 in '55, the 327 didn't come out till '62. And it wasn't offered in the Bel Air with a four-barrel carb till '64. However, in 1964, the correct ignition timing would be four degrees before top-dead-center.
Early Canon FD lenses are identifiable by their metal barrels and silver breech lock rings; later New FD or nFD lenses are all black without the breech lock rings and were built with more plastic, making them less solid but much lighter.
Chevy didn't make a 327 in '55, the 327 didn't come out till '62. And it wasn't offered in the Bel Air with a four-barrel carb till '64. However, in 1964, the correct ignition timing would be four degrees before top-dead-center.