Do you believe everything that is in Wiki's?the 4g64 is a non-interference motor http://en.wikipedia.org/wiki/Mitsubishi_Sirius_engine#4G64
An interference motor is any motor where the valves and pistons share the same space at different times. The 4G64 definitely does that. There is no recessed dome on the 4G64 pistons, let alone valve relief's.
To the OP... The head needs to be resurfaced and you should at least do a valve job on the valves you have to replace or the new valves won't seal properly.