Here is a breather that I got from Napa. In the instruction sheet it says "When used on a 1970, 1971 Plymouth T/A and Dodge AAR Barracuda cap off nipples that are not needed.

4635690-Breather.jpg (94 downloads)
....there is nothing like driving my 1968 Hemi Dart around town and having people looking at you like you're nuts!!