What rear shocks for mnitubbed Dart?
I've been driving mine around for the last two weeks with same Monroe Gas-matic shocks that I was using before the mini-tub and haven't noticed any bottoming yet. Mine is a 67 so that might make a difference.
I would find your stock shock and look up it's specs here...
http://www.monroe.com/catalog_lookup/misc_app_docs/08_MountingLengthSheet.pdf
then, look for a shorter shock with the same ends as your stock one.