What cam would you reconmend for a ASTRON II (aussie spec)? It is the carbie version, so we are looking at a longer duration cam. What are aftermarket cams like for mitsus or will i have to go custom grind?

What is the performance change you are trying to achieve? You should be able to call a machine shop and they'll be able to order the cam for you. You could also switch to longer rods wich may or may not be cheaper.