Heater hose orientation

The only differences I know in the heater cores are; after around 1970 the tubing connections changed to 1/2" and 5/8" instead of both being 5/8". In addition after 73 the core is a little larger. Other than that, I believe that all non-AC heater cores from 64-69 are the same, regardless of engine size. If somebody knows otherwise please chime in, and Rich, it may be time to change radiator shops.