Where to buy neutral safety switch, '68 Dart?

I bought one from the local parts store but it was the 3 pin type. They insisted they had looked it up for a '68, and I guess they did, I just didn't realize at the time there were 2 styles in '68.
I would like to use the original type if possible instead of modifying a 3 pin one.
bremereric, is yours new or used?
I had the trans gone through because it had several leaks. I'm afraid the switch will leak also as the plastic part will turn inside the housing.
Dallas