There are 2 basic flex hoses. They are year dependent
The earlier 8 3/4 have the vent on the hump the later years have the vent on the housing tube
The change happened in 1970
Look on rock auto at the hose for 67 with 8 3/4 then look at 70 you will see the part number change and the length change.
If your car is a 67 but the rear has the vent on the tube you need the hose for the later year cars