A904 to 360

The adapter ring is for the early 904 torque converter snout, pre 1968, to a post 1968 crank. The early converter snout diameter is around 1.5". In 1968 this changed to approximately 1.8". My 1965 Barracuda had a vibration at highway speeds, especially around 65 mph that no amount of tire balancing would take out. When I pulled the old 318, a 1968 vintage, I discovered that it did not have the spacer. I am also swapping in a 360 at this time. As soon as I get my radiator and driveshaft back, I will be able to see if this cures the vibration.