ZMachine was ported using an Amiga 3000 with 6Mb RAM and AmigaOS 2.04. I do not know if it works with AmigaOS 1.3. If it does not, no effort will be made to port it to 1.3 (see ``Copying'' section for info on how to obtain source code.). The ixemul.library definitely requires the 2.04 mathieeesingbas.library, ZMachine does not use floats though, so you might be able to get away with copying over another library in its place (or you could get the library from someone who has 2.04, although I'm not sure if this is legal or not.)
NTSC and PAL displays and all Motorola 680x0 CPU's are supported.
The amount of memory used is determined by the game being played. The average seems to be on the order of 256K.