Bulkhead Connector

I purchased a Bulkhead Connector that is for 1966-74 A Bodies. I will be modifying it to accept some other wiring that will pass through without using the connector as it is designed. I just want to experiment on another of the same style before I move forward with the mods on the purchased one. Not knowing about the '74 van electrical connection I thought I would ask before moving ahead. I am sorry but, my intention was not to be lumping all those in 1 group.
I would be 100% SHOCKED if that connector is correct for ALL those years.