You might try calling the parts dept at Ken Garff Mitsubishi in Salt Lake City. There are actually a lot of older Monteros running around here in SLC and I think Garff has been selling/servicing Mitsu for a long time, although I've only been here for 4 years so I don't know how long. The parts guy there gave me the information.
Edit: Oh, and there are cam seals on the front and back of the motor/head. The rears are an o-ring on a plug that can be changed at any time but are more easily taken care of while you are in there.
Edit: Oh, and there are cam seals on the front and back of the motor/head. The rears are an o-ring on a plug that can be changed at any time but are more easily taken care of while you are in there.