1964 Dart GT - Bought it because my wife likes it.

yes it seems that you have a hydraulic lifter motor or a hydraulic cam, head and rockers.
do you still have the pushbutton trans? (I assume you do) I would definitely find out what year engine you have. The reason is that the newer than 1967 engines are not compatible with the older than 1968 transmissions. This is due to the "register" size of the crank/convertor hub area. this could cause some serious vibration issues.
For whatever reasons, you need to check everything over carefully. It seems that whoever was working on this previously did not have much experience with the slant sixes. Keep us posted, we'll figure it all out! Enjoy ( I too used to have a couple of '64 darts; still got some parts for one)